在EF核心你不再可以执行“自由”原始sql。您需要为该类定义一个POCO类和一个DbSet。 在你的情况下，你需要定义Rank:

var ranks = DbContext.Ranks
   .FromSql("SQL_SCRIPT OR STORED_PROCEDURE @p0,@p1,...etc", parameters)
   .AsNoTracking().ToList();

因为它肯定是只读的，所以包含. asnotracking()调用会很有用。

EF Core 3.0的突破性变化:

DbQuery()现在已经过时了，取而代之的应该是DbSet()。如果你有一个无键实体，即它不需要主键，你可以使用HasNoKey()方法:

ModelBuilder.Entity<SomeModel>().HasNoKey()

更多信息可以在这里找到

你可以在EF Core中执行原始sql -将这个类添加到你的项目中。 这将允许您执行原始SQL并获得原始结果，而不必定义POCO和DBSet。 参见https://github.com/aspnet/EntityFramework/issues/1862#issuecomment-220787464获取原始示例。

using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Internal;
using Microsoft.EntityFrameworkCore.Storage;
using System.Threading;
using System.Threading.Tasks;

namespace Microsoft.EntityFrameworkCore
{
    public static class RDFacadeExtensions
    {
        public static RelationalDataReader ExecuteSqlQuery(this DatabaseFacade databaseFacade, string sql, params object[] parameters)
        {
            var concurrencyDetector = databaseFacade.GetService<IConcurrencyDetector>();

            using (concurrencyDetector.EnterCriticalSection())
            {
                var rawSqlCommand = databaseFacade
                    .GetService<IRawSqlCommandBuilder>()
                    .Build(sql, parameters);

                return rawSqlCommand
                    .RelationalCommand
                    .ExecuteReader(
                        databaseFacade.GetService<IRelationalConnection>(),
                        parameterValues: rawSqlCommand.ParameterValues);
            }
        }

        public static async Task<RelationalDataReader> ExecuteSqlQueryAsync(this DatabaseFacade databaseFacade, 
                                                             string sql, 
                                                             CancellationToken cancellationToken = default(CancellationToken),
                                                             params object[] parameters)
        {

            var concurrencyDetector = databaseFacade.GetService<IConcurrencyDetector>();

            using (concurrencyDetector.EnterCriticalSection())
            {
                var rawSqlCommand = databaseFacade
                    .GetService<IRawSqlCommandBuilder>()
                    .Build(sql, parameters);

                return await rawSqlCommand
                    .RelationalCommand
                    .ExecuteReaderAsync(
                        databaseFacade.GetService<IRelationalConnection>(),
                        parameterValues: rawSqlCommand.ParameterValues,
                        cancellationToken: cancellationToken);
            }
        }
    }
}

下面是一个如何使用它的例子:

// Execute a query.
using(var dr = await db.Database.ExecuteSqlQueryAsync("SELECT ID, Credits, LoginDate FROM SamplePlayer WHERE " +
                                                          "Name IN ('Electro', 'Nitro')"))
{
    // Output rows.
    var reader = dr.DbDataReader;
    while (reader.Read())
    {
        Console.Write("{0}\t{1}\t{2} \n", reader[0], reader[1], reader[2]);
    }
}

现在，直到EFCore有新的东西，我将使用命令 手动映射

  using (var command = this.DbContext.Database.GetDbConnection().CreateCommand())
  {
      command.CommandText = "SELECT ... WHERE ...> @p1)";
      command.CommandType = CommandType.Text;
      var parameter = new SqlParameter("@p1",...);
      command.Parameters.Add(parameter);

      this.DbContext.Database.OpenConnection();

      using (var result = command.ExecuteReader())
      {
         while (result.Read())
         {
            .... // Map to your entity
         }
      }
  }

尝试使用SqlParameter避免Sql注入。

 dbData.Product.FromSql("SQL SCRIPT");

FromSql不支持全查询。例如，如果你想包含一个WHERE子句，它将被忽略。

一些链接:

使用实体框架核心执行原始SQL查询

原始SQL查询

在其他答案的基础上，我写了这个助手来完成这个任务，包括示例用法:

public static class Helper
{
    public static List<T> RawSqlQuery<T>(string query, Func<DbDataReader, T> map)
    {
        using (var context = new DbContext())
        {
            using (var command = context.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = query;
                command.CommandType = CommandType.Text;

                context.Database.OpenConnection();

                using (var result = command.ExecuteReader())
                {
                    var entities = new List<T>();

                    while (result.Read())
                    {
                        entities.Add(map(result));
                    }

                    return entities;
                }
            }
        }
    }

用法:

public class TopUser
{
    public string Name { get; set; }

    public int Count { get; set; }
}

var result = Helper.RawSqlQuery(
    "SELECT TOP 10 Name, COUNT(*) FROM Users U"
    + " INNER JOIN Signups S ON U.UserId = S.UserId"
    + " GROUP BY U.Name ORDER BY COUNT(*) DESC",
    x => new TopUser { Name = (string)x[0], Count = (int)x[1] });

result.ForEach(x => Console.WriteLine($"{x.Name,-25}{x.Count}"));

我计划在添加内置支持后尽快摆脱它。根据EF核心团队的Arthur Vickers的声明，这是2.0后的优先级。这个问题正在被追踪。

如果您使用EF Core 3.0或更新版本

你需要使用无键实体类型，以前称为查询类型:

该特性是在EF Core 2.1中以查询类型的名称添加的。 在EF Core 3.0中，这个概念被重命名为无键实体类型。的 [无键]数据注释在EFCore 5.0中可用。

要使用它们，你需要首先用[Keyless]数据注释标记你的类SomeModel，或者通过.HasNoKey()方法调用进行流畅配置，如下所示:

public DbSet<SomeModel> SomeModels { get; set; }

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<SomeModel>().HasNoKey();
}

配置完成后，可以使用这里解释的方法之一来执行SQL查询。例如，你可以用这个:

var result = context.SomeModels.FromSqlRaw("SQL SCRIPT").ToList();
var result = await context.SomeModels.FromSql("SQL_SCRIPT").ToListAsync();

如果您正在使用EF Core 2.1

如果您正在使用2018年5月7日发布的EF Core 2.1候选版本1，您可以利用提议的新功能，即查询类型:

除了实体类型，EF Core模型还可以包含查询类型， 哪些可以用于对数据进行数据库查询 没有映射到实体类型。

什么时候使用查询类型?

作为临时FromSql()查询的返回类型。 映射到数据库视图。 映射到没有定义主键的表。 映射到模型中定义的查询。

所以你不再需要做所有的黑客或变通方法来回答你的问题。只需遵循以下步骤:

首先，您定义了一个DbQuery<T>类型的新属性，其中T是将携带SQL查询列值的类的类型。在你的DbContext中，你会有这个:

public DbQuery<SomeModel> SomeModels { get; set; }

其次，使用FromSql方法，就像使用DbSet<T>一样:

var result = context.SomeModels.FromSql("SQL_SCRIPT").ToList();
var result = await context.SomeModels.FromSql("SQL_SCRIPT").ToListAsync();

还要注意dbcontext是部分类，所以你可以创建一个或多个单独的文件来组织最适合你的“原始SQL DbQuery”定义。

在Core 2.1中，你可以这样做:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
       modelBuilder.Query<Ranks>();
}

然后定义SQL过程，像这样:

public async Task<List<Ranks>> GetRanks(string value1, Nullable<decimal> value2)
{
    SqlParameter value1Input = new SqlParameter("@Param1", value1?? (object)DBNull.Value);
    SqlParameter value2Input = new SqlParameter("@Param2", value2?? (object)DBNull.Value);

    List<Ranks> getRanks = await this.Query<Ranks>().FromSql("STORED_PROCEDURE @Param1, @Param2", value1Input, value2Input).ToListAsync();

    return getRanks;
}

这样就不会在数据库中创建rank模型。

现在在你的控制器/动作中你可以调用:

List<Ranks> gettingRanks = _DbContext.GetRanks(value1,value2).Result.ToListAsync();

这样就可以调用原始SQL过程。

我使用Dapper绕过了Entity框架Core的这个约束。

IDbConnection.Query

正在处理带有多个参数的SQL查询或存储过程。 顺便说一下，它更快一些(参见基准测试)

Dapper很容易学。编写和运行带参数的存储过程需要15分钟。无论如何，你可以同时使用EF和Dapper。下面是一个例子:

 public class PodborsByParametersService
{
    string _connectionString = null;


    public PodborsByParametersService(string connStr)
    {
        this._connectionString = connStr;

    }

    public IList<TyreSearchResult> GetTyres(TyresPodborView pb,bool isPartner,string partnerId ,int pointId)
    {

        string sqltext  "spGetTyresPartnerToClient";

        var p = new DynamicParameters();
        p.Add("@PartnerID", partnerId);
        p.Add("@PartnerPointID", pointId);

        using (IDbConnection db = new SqlConnection(_connectionString))
        {
            return db.Query<TyreSearchResult>(sqltext, p,null,true,null,CommandType.StoredProcedure).ToList();
        }


        }
}

你也可以使用QueryFirst。和Dapper一样，这完全不在EF的范围内。与Dapper(或EF)不同的是，您不需要维护POCO，只需在真实环境中编辑sql sql，并根据DB不断对其进行重新验证。免责声明:我是QueryFirst的作者。

添加Nuget包- Microsoft.EntityFrameworkCore.Relational

using Microsoft.EntityFrameworkCore;
...
await YourContext.Database.ExecuteSqlCommandAsync("... @p0, @p1", param1, param2 ..)

这将以int形式返回行号

参见- https://learn.microsoft.com/en-us/dotnet/api/microsoft.entityframeworkcore.relationaldatabasefacadeextensions.executesqlcommand?view=efcore-3.0

不是直接针对OP的场景，但因为我一直在努力解决这个问题，我想放弃这些让DbContext更容易执行原始SQL的ex.方法:

public static class DbContextCommandExtensions
{
  public static async Task<int> ExecuteNonQueryAsync(this DbContext context, string rawSql,
    params object[] parameters)
  {
    var conn = context.Database.GetDbConnection();
    using (var command = conn.CreateCommand())
    {
      command.CommandText = rawSql;
      if (parameters != null)
        foreach (var p in parameters)
          command.Parameters.Add(p);
      await conn.OpenAsync();
      return await command.ExecuteNonQueryAsync();
    }
  }

  public static async Task<T> ExecuteScalarAsync<T>(this DbContext context, string rawSql,
    params object[] parameters)
  {
    var conn = context.Database.GetDbConnection();
    using (var command = conn.CreateCommand())
    {
      command.CommandText = rawSql;
      if (parameters != null)
        foreach (var p in parameters)
          command.Parameters.Add(p);
      await conn.OpenAsync();
      return (T)await command.ExecuteScalarAsync();
    }
  }
}

你可以用这个:

public static class SqlQueryExtensions
{
    public static IList<T> SqlQuery<T>(this DbContext db, string sql, params object[] parameters) where T : class
    {
        using (var db2 = new ContextForQueryType<T>(db.Database.GetDbConnection()))
        {
            // share the current database transaction, if one exists
            var transaction = db.Database.CurrentTransaction;
            if (transaction != null)
                db2.Database.UseTransaction(transaction.GetDbTransaction());
            return db2.Set<T>().FromSqlRaw(sql, parameters).ToList();
        }
    }

    private class ContextForQueryType<T> : DbContext where T : class
    {
        private readonly DbConnection connection;

        public ContextForQueryType(DbConnection connection)
        {
            this.connection = connection;
        }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer(connection, options => options.EnableRetryOnFailure());

            base.OnConfiguring(optionsBuilder);
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<T>().HasNoKey();
            base.OnModelCreating(modelBuilder);
        }
    }
}

以及用法:

    using (var db = new Db())
    {
        var results = db.SqlQuery<ArbitraryType>("select 1 id, 'joe' name");
        //or with an anonymous type like this
        var results2 = db.SqlQuery(() => new { id =1, name=""},"select 1 id, 'joe' name");
    }

在实体框架6中，你可以执行如下内容

创建模态类为

Public class User
{
        public int Id { get; set; }
        public string fname { get; set; }
        public string lname { get; set; }
        public string username { get; set; }
}

执行Raw DQL SQl命令如下所示:

var userList = datacontext.Database.SqlQuery<User>(@"SELECT u.Id ,fname , lname ,username FROM dbo.Users").ToList<User>();

试试这个(创建扩展方法)

public static List<T> ExecuteQuery<T>(this dbContext db, string query) where T : class, new()
        {
            using (var command = db.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = query;
                command.CommandType = CommandType.Text;

                db.Database.OpenConnection();

                using (var reader = command.ExecuteReader())
                {
                    var lst = new List<T>();
                    var lstColumns = new T().GetType().GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).ToList();
                    while (reader.Read())
                    {
                        var newObject = new T();
                        for (var i = 0; i < reader.FieldCount; i++)
                        {
                            var name = reader.GetName(i);
                            PropertyInfo prop = lstColumns.FirstOrDefault(a => a.Name.ToLower().Equals(name.ToLower()));
                            if (prop == null)
                            {
                                continue;
                            }
                            var val = reader.IsDBNull(i) ? null : reader[i];
                            prop.SetValue(newObject, val, null);
                        }
                        lst.Add(newObject);
                    }

                    return lst;
                }
            }
        }

用法:

var db = new dbContext();
string query = @"select ID , Name from People where ... ";
var lst = db.ExecuteQuery<PeopleView>(query);

我的模型:(不在DbSet中):

public class PeopleView
{
    public int ID { get; set; }
    public string Name { get; set; }
}

在。net core 2.2和3.0中测试。

注意:该方案性能较慢

我的案例使用了存储过程而不是原始SQL

创建一个类

Public class School
{
    [Key]
    public Guid SchoolId { get; set; }
    public string Name { get; set; }
    public string Branch { get; set; }
    public int NumberOfStudents  { get; set; }
}

下面在我的DbContext类上添加

public DbSet<School> SP_Schools { get; set; }

执行存储过程。

var MySchools = _db.SP_Schools.FromSqlRaw("GetSchools @schoolId, @page, @size ",
              new SqlParameter("schoolId", schoolId),
              new SqlParameter("page", page),
              new SqlParameter("size", size)))
.IgnoreQueryFilters();

这个解决方案很大程度上依赖于@pius的解决方案。我想添加支持查询参数的选项，以帮助减少SQL注入，我还想使它成为实体框架核心的DbContext DatabaseFacade的扩展，使它更加集成。

首先用扩展名创建一个新类:

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Metadata;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Threading.Tasks;

namespace EF.Extend
{

    public static class ExecuteSqlExt
    {
        /// <summary>
        /// Execute raw SQL query with query parameters
        /// </summary>
        /// <typeparam name="T">the return type</typeparam>
        /// <param name="db">the database context database, usually _context.Database</param>
        /// <param name="query">the query string</param>
        /// <param name="map">the map to map the result to the object of type T</param>
        /// <param name="queryParameters">the collection of query parameters, if any</param>
        /// <returns></returns>
        public static List<T> ExecuteSqlRawExt<T, P>(this DatabaseFacade db, string query, Func<DbDataReader, T> map, IEnumerable<P> queryParameters = null)
        {
            using (var command = db.GetDbConnection().CreateCommand())
            {
                if((queryParameters?.Any() ?? false))
                    command.Parameters.AddRange(queryParameters.ToArray());

                command.CommandText = query;
                command.CommandType = CommandType.Text;

                db.OpenConnection();

                using (var result = command.ExecuteReader())
                {
                    var entities = new List<T>();

                    while (result.Read())
                    {
                        entities.Add(map(result));
                    }

                    return entities;
                }
            }
                
        }
    }

}

注意上面的“T”是返回的类型，“P”是查询参数的类型，这取决于你是否使用MySql、Sql等。

接下来我们将展示一个例子。我使用的是MySql EF核心功能，所以我们将看到如何使用上面的通用扩展与这个更具体的MySql实现:

//add your using statement for the extension at the top of your Controller
//with all your other using statements
using EF.Extend;

//then your your Controller looks something like this
namespace Car.Api.Controllers
{

    //Define a quick Car class for the custom return type
    //you would want to put this in it's own class file probably
    public class Car
    {
        public string Make { get; set; }
        public string Model { get; set; }
        public string DisplayTitle { get; set; }
    }

    [ApiController]
    public class CarController : ControllerBase
    {
        private readonly ILogger<CarController> _logger;
        //this would be your Entity Framework Core context
        private readonly CarContext _context;

        public CarController(ILogger<CarController> logger, CarContext context)
        {
            _logger = logger;
            _context = context;
        }

        //... more stuff here ...

       /// <summary>
       /// Get car example
       /// </summary>
       [HttpGet]
       public IEnumerable<Car> Get()
       {
           //instantiate three query parameters to pass with the query
           //note the MySqlParameter type is because I'm using MySql
           MySqlParameter p1 = new MySqlParameter
           {
               ParameterName = "id1",
               Value = "25"
           };

           MySqlParameter p2 = new MySqlParameter
           {
               ParameterName = "id2",
               Value = "26"
           };

           MySqlParameter p3 = new MySqlParameter
           {
               ParameterName = "id3",
               Value = "27"
           };

           //add the 3 query parameters to an IEnumerable compatible list object
           List<MySqlParameter> queryParameters = new List<MySqlParameter>() { p1, p2, p3 };

           //note the extension is now easily accessed off the _context.Database object
           //also note for ExecuteSqlRawExt<Car, MySqlParameter>
           //Car is my return type "T"
           //MySqlParameter is the specific DbParameter type MySqlParameter type "P"
           List<Car> result = _context.Database.ExecuteSqlRawExt<Car, MySqlParameter>(
        "SELECT Car.Make, Car.Model, CONCAT_WS('', Car.Make, ' ', Car.Model) As DisplayTitle FROM Car WHERE Car.Id IN(@id1, @id2, @id3)",
        x => new Car { Make = (string)x[0], Model = (string)x[1], DisplayTitle = (string)x[2] }, 
        queryParameters);

           return result;
       }
    }
}

查询将返回如下行: “福特”，“探险家”，“福特探险家” “特斯拉”，“Model X”，“特斯拉Model X”

显示标题没有定义为数据库列，因此默认情况下它不是EF Car模型的一部分。作为众多可能的解决方案之一，我喜欢这种方法。本页上的其他答案引用了使用[NotMapped]装饰器解决此问题的其他方法，这取决于您的用例，可能是更合适的方法。

注意，本例中的代码显然比实际需要的更冗长，但我认为它使示例更清晰。

实际上，您可以创建一个通用的存储库并做类似的事情

public class GenericRepository<TEntity> : IGenericRepository<TEntity> where TEntity : BaseEntity
{
    private readonly DataContext context;
    private readonly DbSet<TEntity> dbSet;

    public GenericRepository(DataContext context)
    {
        this.context = context;
        this.dbSet = context.Set<TEntity>();
    }

   
    public IEnumerable<TEntity> ExecuteCommandQuery(string command)
        => dbSet.FromSqlRaw(command);

}

我更新了扩展方法从@AminRostami返回IAsyncEnumerable(这样LINQ过滤可以应用)，它的映射模型列名的记录从DB返回到模型(EF Core 5测试):

扩展本身:

public static class QueryHelper
{
    private static string GetColumnName(this MemberInfo info)
    {
        List<ColumnAttribute> list = info.GetCustomAttributes<ColumnAttribute>().ToList();
        return list.Count > 0 ? list.Single().Name : info.Name;
    }
    /// <summary>
    /// Executes raw query with parameters and maps returned values to column property names of Model provided.
    /// Not all properties are required to be present in model (if not present - null)
    /// </summary>
    public static async IAsyncEnumerable<T> ExecuteQuery<T>(
        [NotNull] this DbContext db,
        [NotNull] string query,
        [NotNull] params SqlParameter[] parameters)
        where T : class, new()
    {
        await using DbCommand command = db.Database.GetDbConnection().CreateCommand();
        command.CommandText = query;
        command.CommandType = CommandType.Text;
        if (parameters != null)
        {
            foreach (SqlParameter parameter in parameters)
            {
                command.Parameters.Add(parameter);
            }
        }
        await db.Database.OpenConnectionAsync();
        await using DbDataReader reader = await command.ExecuteReaderAsync();
        List<PropertyInfo> lstColumns = new T().GetType()
            .GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic).ToList();
        while (await reader.ReadAsync())
        {
            T newObject = new();
            for (int i = 0; i < reader.FieldCount; i++)
            {
                string name = reader.GetName(i);
                PropertyInfo prop = lstColumns.FirstOrDefault(a => a.GetColumnName().Equals(name));
                if (prop == null)
                {
                    continue;
                }
                object val = await reader.IsDBNullAsync(i) ? null : reader[i];
                prop.SetValue(newObject, val, null);
            }
            yield return newObject;
        }
    }
}

使用的模型(注意列名与实际的属性名不同):

public class School
{
    [Key] [Column("SCHOOL_ID")] public int SchoolId { get; set; }

    [Column("CLOSE_DATE", TypeName = "datetime")]
    public DateTime? CloseDate { get; set; }

    [Column("SCHOOL_ACTIVE")] public bool? SchoolActive { get; set; }
}

实际的用法:

public async Task<School> ActivateSchool(int schoolId)
{
    // note that we're intentionally not returning "SCHOOL_ACTIVE" with select statement
    // this might be because of certain IF condition where we return some other data
    return await _context.ExecuteQuery<School>(
        "UPDATE SCHOOL SET SCHOOL_ACTIVE = 1 WHERE SCHOOL_ID = @SchoolId; SELECT SCHOOL_ID, CLOSE_DATE FROM SCHOOL",
        new SqlParameter("@SchoolId", schoolId)
    ).SingleAsync();
}

我之所以提出这个问题，是因为我们在实体框架6中有超过100个SqlQuery的无实体使用实例，所以按照微软建议的方式在我们的例子中并不容易工作。

此外，在从EF迁移到EFC的过程中，我们不得不维持一个EF(实体框架6)/ EFC(实体框架核心5)代码库好几个月。代码库相当大，根本不可能“一夜之间”迁移。

下面的答案是基于上面的答案，这只是一个小的扩展，使它们适用于更多的边缘情况。

首先，对于每个基于EF的项目，我们创建了一个基于EFC的项目(例如MyProject)。csproj ==> MyProject_EFC.csproj)，在所有这样的EFC项目中我们定义了常量EFCORE。如果你正在做一个快速的一次性迁移从EF到EFC，那么你不需要，你可以保持什么里面# If EFCORE…删除#else里面的内容# endif下面。

下面是主要的互操作扩展类。

using System;
using System.Collections.Generic;
using System.Threading;

#if EFCORE
using System.ComponentModel.DataAnnotations.Schema;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Microsoft.EntityFrameworkCore.Storage;
using Database = Microsoft.EntityFrameworkCore.Infrastructure.DatabaseFacade;
using MoreLinq.Extensions;
#else
using System.Data.Entity;
using System.Data.Entity.Infrastructure;
#endif

namespace YourNameSpace.EntityFrameworkCore
{
    /// <summary>
    /// Collection of extension methods to simplify migration from EF to EFC.
    /// </summary>
    public static class EntityFrameworkCoreInterop
    {
        /// <summary>
        /// https://stackoverflow.com/questions/6637679/reflection-get-attribute-name-and-value-on-property
        /// </summary>
        public static TAttribute? TryGetAttribute<TAttribute>(this PropertyInfo prop) where TAttribute : Attribute =>
            prop.GetCustomAttributes(true).TryGetAttribute<TAttribute>();

        public static TAttribute? TryGetAttribute<TAttribute>(this Type t) where TAttribute : Attribute =>
            t.GetCustomAttributes(true).TryGetAttribute<TAttribute>();

        public static TAttribute? TryGetAttribute<TAttribute>(this IEnumerable<object> attrs) where TAttribute : Attribute
        {
            foreach (object attr in attrs)
            {
                switch (attr)
                {
                    case TAttribute t:
                    {
                        return t;
                    }
                }
            }

            return null;
        }

        /// <summary>
        /// Returns true if the source string matches *any* of the passed-in strings (case insensitive)
        /// </summary>
        public static bool EqualsNoCase(this string? s, params string?[]? targets)
        {
            if (s == null && (targets == null || targets.Length == 0))
            {
                return true;
            }

            if (targets == null)
            {
                return false;
            }

            return targets.Any(t => string.Equals(s, t, StringComparison.OrdinalIgnoreCase));
        }

#if EFCORE
        public class EntityException : Exception
        {
            public EntityException(string message) : base(message)
            {
            }
        }

        public static TEntity GetEntity<TEntity>(this EntityEntry<TEntity> entityEntry)
            where TEntity : class => entityEntry.Entity;

        #region SqlQuery Interop

        /// <summary>
        /// kk:20210727 - This is a little bit ugly but given that this interop method is used just once,
        /// it is not worth spending more time on it.
        /// </summary>
        public static List<T> ToList<T>(this IOrderedAsyncEnumerable<T> e) =>
            Task.Run(() => e.ToListAsync().AsTask()).GetAwaiter().GetResult();

        private static string GetColumnName(this MemberInfo info) =>
            info.GetCustomAttributes().TryGetAttribute<ColumnAttribute>()?.Name ?? info.Name;

        /// <summary>
        /// See: https://stackoverflow.com/questions/35631903/raw-sql-query-without-dbset-entity-framework-core
        /// Executes raw query with parameters and maps returned values to column property names of Model provided.
        /// Not all properties are required to be present in the model. If not present then they will be set to nulls.
        /// </summary>
        private static async IAsyncEnumerable<T> ExecuteQuery<T>(this Database database, string query, params object[] parameters)
        {
            await using DbCommand command = database.GetDbConnection().CreateCommand();
            command.CommandText = query;
            command.CommandType = CommandType.Text;

            if (database.CurrentTransaction != null)
            {
                command.Transaction = database.CurrentTransaction.GetDbTransaction();
            }

            foreach (var parameter in parameters)
            {
                // They are supposed to be of SqlParameter type but are passed as objects.
                command.Parameters.Add(parameter);
            }

            await database.OpenConnectionAsync();
            await using DbDataReader reader = await command.ExecuteReaderAsync();
            var t = typeof(T);

            // TODO kk:20210825 - I do know that the code below works as we use it in some other place where it does work.
            // However, I am not 100% sure that R# proposed version does. Check and refactor when time permits.
            //
            // ReSharper disable once CheckForReferenceEqualityInstead.1
            if (t.IsGenericType && t.GetGenericTypeDefinition().Equals(typeof(Nullable<>)))
            {
                t = Nullable.GetUnderlyingType(t)!;
            }

            var lstColumns = t
                .GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
                .ToList();

            while (await reader.ReadAsync())
            {
                if (t.IsPrimitive || t == typeof(string) || t == typeof(DateTime) || t == typeof(Guid) || t == typeof(decimal))
                {
                    var val = await reader.IsDBNullAsync(0) ? null : reader[0];
                    yield return (T) val!;
                }
                else
                {
                    var newObject = Activator.CreateInstance<T>();

                    for (var i = 0; i < reader.FieldCount; i++)
                    {
                        var name = reader.GetName(i);
                        var val = await reader.IsDBNullAsync(i) ? null : reader[i];
                        var prop = lstColumns.FirstOrDefault(a => a.GetColumnName().EqualsNoCase(name));

                        if (prop == null)
                        {
                            continue;
                        }

                        prop.SetValue(newObject, val, null);
                    }

                    yield return newObject;
                }
            }
        }

        #endregion

        public static DbRawSqlQuery<TElement> SqlQuery<TElement>(this Database database, string sql, params object[] parameters) =>
            new(database, sql, parameters);

        public class DbRawSqlQuery<TElement> : IAsyncEnumerable<TElement>
        {
            private readonly IAsyncEnumerable<TElement> _elements;

            internal DbRawSqlQuery(Database database, string sql, params object[] parameters) =>
                _elements = ExecuteQuery<TElement>(database, sql, parameters);

            public IAsyncEnumerator<TElement> GetAsyncEnumerator(CancellationToken cancellationToken = new ()) =>
                _elements.GetAsyncEnumerator(cancellationToken);

            public async Task<TElement> SingleAsync() => await _elements.SingleAsync();
            public TElement Single() => Task.Run(SingleAsync).GetAwaiter().GetResult();
            public async Task<TElement> FirstAsync() => await _elements.FirstAsync();
            public TElement First() => Task.Run(FirstAsync).GetAwaiter().GetResult();
            public async Task<TElement?> SingleOrDefaultAsync() => await _elements.SingleOrDefaultAsync();
            public async Task<int> CountAsync() => await _elements.CountAsync();
            public async Task<List<TElement>> ToListAsync() => await _elements.ToListAsync();
            public List<TElement> ToList() => Task.Run(ToListAsync).GetAwaiter().GetResult();

        }
#endif
    }
}

用法与以前的EF用法没有区别:

public async Task<List<int>> GetMyResults()
{
    using var ctx = GetMyDbContext();
    const string sql = "select 1 as Result";
    return await ctx.GetDatabase().SqlQuery<int>(sql).ToListAsync();
}

其中GetMyDbContext是一个获取数据库上下文的方法，GetDatabase是一个返回((DbContext)上下文的一行互操作。给定IMyDbContext的数据库:DbContext。这是为了简化同时进行的EF / EFC操作。

这适用于基本类型(上面的例子)、实体、本地类(但不包括匿名类)。通过GetColumnName支持列重命名，但是，…上面已经做过了。

查询数据:不存在实体

               string query = "SELECT r.Name as roleName, ur.roleId, u.Id as userId   FROM dbo.AspNetUserRoles AS ur INNER JOIN dbo.AspNetUsers AS u ON ur.UserId = u.Id INNER JOIN dbo.AspNetRoles AS r ON ur.RoleId = r.Id ";

               ICollection<object> usersWithRoles = new List<object>();
                using (var command = _identityDBContext.Database.GetDbConnection().CreateCommand())
                {
                    command.CommandText = query;
                    command.CommandType = CommandType.Text;

                    await _identityDBContext.Database.OpenConnectionAsync();

                    using (var reader = await command.ExecuteReaderAsync())
                    {      
                        while (await reader.ReadAsync())
                        {
                            usersWithRoles.Add(new { 
                                roleName = reader.GetFieldValueAsync<string>(0).Result, 
                                roleId = reader.GetFieldValueAsync<string>(1).Result,
                                userId = reader.GetFieldValueAsync<string>(2).Result
                            });
                        }    
                    }
                }

详细:

 [HttpGet]
    [Route("GetAllUsersWithRoles")]
    public async Task<IActionResult> GetAllUsersWithRoles()
    {
        string query = "SELECT r.Name as roleName, ur.roleId, u.Id as userId   FROM dbo.AspNetUserRoles AS ur INNER JOIN dbo.AspNetUsers AS u ON ur.UserId = u.Id INNER JOIN dbo.AspNetRoles AS r ON ur.RoleId = r.Id ";
        try
        {
            ICollection<object> usersWithRoles = new List<object>();
            using (var command = _identityDBContext.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = query;
                command.CommandType = CommandType.Text;

                await _identityDBContext.Database.OpenConnectionAsync();

                using (var reader = await command.ExecuteReaderAsync())
                {      
                    while (await reader.ReadAsync())
                    {
                        usersWithRoles.Add(new { 
                            roleName = reader.GetFieldValueAsync<string>(0).Result, 
                            roleId = reader.GetFieldValueAsync<string>(1).Result,
                            userId = reader.GetFieldValueAsync<string>(2).Result
                        });
                    }    
                }
            }
                return StatusCode(200, usersWithRoles); // Get all users   
        }
        catch (Exception e)
        {
            return StatusCode(500, e);
        }
    }

结果如下所示:

[
  {
    "roleName": "admin",
    "roleId": "7c9cb1be-e987-4ec1-ae4d-e4c9790f57d8",
    "userId": "12eadc86-6311-4d5e-8be8-df30799df265"
  },
  {
    "roleName": "user",
    "roleId": "a0d5ef46-b1e6-4a53-91ce-9ff5959f1ed8",
    "userId": "12eadc86-6311-4d5e-8be8-df30799df265"
  },
  {
    "roleName": "user",
    "roleId": "a0d5ef46-b1e6-4a53-91ce-9ff5959f1ed8",
    "userId": "3e7cd970-8c52-4dd1-847c-f824671ea15d"
  }
]

这样做的实体框架核心5，需要安装

Microsoft.EntityFrameworkCore.Relational

助手扩展方法

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Storage;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;


public static class EfHelper
{
    public static DbTransaction GetDbTransaction(this IDbContextTransaction source)
    {
        return (source as IInfrastructure<DbTransaction>).Instance;
    }

    private class PropertyMapp
    {
        public string Name { get; set; }
        public Type Type { get; set; }

        public bool IsSame(PropertyMapp mapp)
        {
            if (mapp == null)
            {
                return false;
            }
            bool same = mapp.Name == Name && mapp.Type == Type;
            return same;
        }
    }

    public static IEnumerable<T> FromSqlQuery<T>(this DbContext context, string query, params object[] parameters) where T : new()
    {
        const BindingFlags flags = BindingFlags.Public | BindingFlags.Instance | BindingFlags.NonPublic;
        List<PropertyMapp> entityFields = (from PropertyInfo aProp in typeof(T).GetProperties(flags)
                                           select new PropertyMapp
                                           {
                                               Name = aProp.Name,
                                               Type = Nullable.GetUnderlyingType(aProp.PropertyType) ?? aProp.PropertyType
                                           }).ToList();
        List<PropertyMapp> dbDataReaderFields = new List<PropertyMapp>();
        List<PropertyMapp> commonFields = null;

        using (var command = context.Database.GetDbConnection().CreateCommand())
        {
            if (command.Connection.State != ConnectionState.Open)
            {
                command.Connection.Open();
            }
            var currentTransaction = context.Database.CurrentTransaction;
            if (currentTransaction != null)
            {
                command.Transaction = currentTransaction.GetDbTransaction();
            }
            command.CommandText = query;
            if (parameters.Any())
            {
                command.Parameters.AddRange(parameters);
            }
            using (var result = command.ExecuteReader())
            {
                while (result.Read())
                {
                    if (commonFields == null)
                    {
                        for (int i = 0; i < result.FieldCount; i++)
                        {
                            dbDataReaderFields.Add(new PropertyMapp { Name = result.GetName(i), Type = result.GetFieldType(i) });
                        }
                        commonFields = entityFields.Where(x => dbDataReaderFields.Any(d => d.IsSame(x))).Select(x => x).ToList();
                    }

                    var entity = new T();
                    foreach (var aField in commonFields)
                    {
                        PropertyInfo propertyInfos = entity.GetType().GetProperty(aField.Name);
                        var value = (result[aField.Name] == DBNull.Value) ? null : result[aField.Name]; //if field is nullable
                        propertyInfos.SetValue(entity, value, null);
                    }
                    yield return entity;
                }
            }
        }
    }

    /*
     * https://entityframeworkcore.com/knowledge-base/35631903/raw-sql-query-without-dbset---entity-framework-core
     */
    public static IEnumerable<T> FromSqlQuery<T>(this DbContext context, string query, Func<DbDataReader, T> map, params object[] parameters)
    {
        using (var command = context.Database.GetDbConnection().CreateCommand())
        {
            if (command.Connection.State != ConnectionState.Open)
            {
                command.Connection.Open();
            }
            var currentTransaction = context.Database.CurrentTransaction;
            if (currentTransaction != null)
            {
                command.Transaction = currentTransaction.GetDbTransaction();
            }
            command.CommandText = query;
            if (parameters.Any())
            {
                command.Parameters.AddRange(parameters);
            }
            using (var result = command.ExecuteReader())
            {
                while (result.Read())
                {
                    yield return map(result);
                }
            }
        }
    }
}

模型

public class UserModel
{
    public string Name { get; set; }
    public string Email { get; set; }
    public bool? IsDeleted { get; set; }
}

手动映射

List<UserModel> usersInDb = Db.FromSqlQuery
(
    "SELECT Name, Email FROM Users WHERE Name=@paramName",
    x => new UserModel 
    { 
        Name = (string)x[0], 
        Email = (string)x[1] 
    },
    new SqlParameter("@paramName", user.Name)
)
.ToList();

usersInDb = Db.FromSqlQuery
(
    "SELECT Name, Email FROM Users WHERE Name=@paramName",
    x => new UserModel 
    { 
        Name = x["Name"] is DBNull ? "" : (string)x["Name"], 
        Email = x["Email"] is DBNull ? "" : (string)x["Email"] 
    },
    new SqlParameter("@paramName", user.Name)
)
.ToList();

使用反射自动映射

List<UserModel> usersInDb = Db.FromSqlQuery<UserModel>
(
    "SELECT Name, Email, IsDeleted FROM Users WHERE Name=@paramName",
    new SqlParameter("@paramName", user.Name)
)
.ToList();

我找到了EntityFrameworkCore包。RawSQLExtensions在github上。要使用它，添加nuget包。

<PackageReference Include="EntityFrameworkCore.RawSQLExtensions" Version="1.2.0" />

这个库没有文档，但下面是我在。net 6 + EF Core 6 + Npgsql 6中使用它

public class DbResult
{
    public string Name { get; set; }
    public int Age { get; set; }
}

using EntityFrameworkCore.RawSQLExtensions.Extensions;

var results = await context.Database
    .SqlQuery<DbResult>(
        @"select name, age from ""users"" where age > @Age",
        new NpgsqlParameter("@Age", 15))
    .ToListAsync();