还要确保你没有像这样用圆括号括起你的查询字符串:

SELECT Name from [USER] WHERE [UserId] in (@ids)

我使用Dapper 1.50.2导致SQL语法错误，通过删除括号来修复

SELECT Name from [USER] WHERE [UserId] in @ids

不需要像在常规SQL中那样在WHERE子句中添加()。因为达普会自动帮我们做。语法如下:-

const string SQL = "SELECT IntegerColumn, StringColumn FROM SomeTable WHERE IntegerColumn IN @listOfIntegers";

var conditions = new { listOfIntegers };
    
var results = connection.Query(SQL, conditions);

postgres的示例:

string sql = "SELECT * FROM SomeTable WHERE id = ANY(@ids)"
var results = conn.Query(sql, new { ids = new[] { 1, 2, 3, 4, 5 }});

根据我的经验，处理这个问题最友好的方法是使用一个函数将字符串转换为值表。

在网络上有很多可用的分配器函数，如果你喜欢SQL，你很容易就能找到一个。

然后你可以做…

SELECT * FROM table WHERE id IN (SELECT id FROM split(@list_of_ids))

Or

SELECT * FROM table INNER JOIN (SELECT id FROM split(@list_of_ids)) AS list ON list.id = table.id

(或相似的)

直接从GitHub项目主页:

Dapper允许您传入IEnumerable，并将自动参数化您的查询。

connection.Query<int>(
    @"select * 
      from (select 1 as Id union all select 2 union all select 3) as X 
      where Id in @Ids", 
    new { Ids = new int[] { 1, 2, 3 });

将译为:

select * 
from (select 1 as Id union all select 2 union all select 3) as X 
where Id in (@Ids1, @Ids2, @Ids3)

// @Ids1 = 1 , @Ids2 = 2 , @Ids2 = 3

SELECT * FROM tbl WHERE col IN @val

我还注意到这种语法不适用于byte[]。Dapper只接受最后一个元素，参数必须用圆括号括起来。 然而，当我将类型更改为int[]时，一切正常。