在ColdFusion中，我们只需要:

<cfset myvalues = "ruby|rails|scruffy|rubyonrails">
    <cfquery name="q">
        select * from sometable where values in <cfqueryparam value="#myvalues#" list="true">
    </cfquery>

在ColdFusion中，我们只需要:

<cfset myvalues = "ruby|rails|scruffy|rubyonrails">
    <cfquery name="q">
        select * from sometable where values in <cfqueryparam value="#myvalues#" list="true">
    </cfquery>

I think this is a case when a static query is just not the way to go. Dynamically build the list for your in clause, escape your single quotes, and dynamically build SQL. In this case you probably won't see much of a difference with any method due to the small list, but the most efficient method really is to send the SQL exactly as it is written in your post. I think it is a good habit to write it the most efficient way, rather than to do what makes the prettiest code, or consider it bad practice to dynamically build SQL.

I have seen the split functions take longer to execute than the query themselves in many cases where the parameters get large. A stored procedure with table valued parameters in SQL 2008 is the only other option I would consider, although this will probably be slower in your case. TVP will probably only be faster for large lists if you are searching on the primary key of the TVP, because SQL will build a temporary table for the list anyway (if the list is large). You won't know for sure unless you test it.

I have also seen stored procedures that had 500 parameters with default values of null, and having WHERE Column1 IN (@Param1, @Param2, @Param3, ..., @Param500). This caused SQL to build a temp table, do a sort/distinct, and then do a table scan instead of an index seek. That is essentially what you would be doing by parameterizing that query, although on a small enough scale that it won't make a noticeable difference. I highly recommend against having NULL in your IN lists, as if that gets changed to a NOT IN it will not act as intended. You could dynamically build the parameter list, but the only obvious thing that you would gain is that the objects would escape the single quotes for you. That approach is also slightly slower on the application end since the objects have to parse the query to find the parameters. It may or may not be faster on SQL, as parameterized queries call sp_prepare, sp_execute for as many times you execute the query, followed by sp_unprepare.

重用存储过程或参数化查询的执行计划可能会提高性能，但它会将您锁定在由执行的第一个查询决定的执行计划中。在许多情况下，这对于后续查询可能不太理想。在您的情况下，重用执行计划可能是一个加分项，但它可能根本没有任何区别，因为示例是一个非常简单的查询。

悬崖笔记:

对于您的情况，您所做的任何事情，无论是使用列表中固定数量的项进行参数化(如果不使用则为空)，动态地构建带有或不带有参数的查询，还是使用带有表值参数的存储过程，都不会产生太大的区别。不过，我的一般建议如下:

你的case/简单查询很少参数:

动态SQL，如果测试显示更好的性能，可能会使用参数。

具有可重用执行计划的查询，通过简单地更改参数或如果查询很复杂则调用多次:

带有动态参数的SQL。

带有大列表的查询:

具有表值参数的存储过程。如果列表变化很大，则在存储过程上使用WITH RECOMPILE，或者简单地使用不带参数的动态SQL为每个查询生成新的执行计划。

唯一的制胜方法就是不玩。

对你来说没有无限的可变性。只有有限的可变性。

在SQL中，你有这样一个子句:

and ( {1}==0 or b.CompanyId in ({2},{3},{4},{5},{6}) )

在c#代码中，你可以这样做:

  int origCount = idList.Count;
  if (origCount > 5) {
    throw new Exception("You may only specify up to five originators to filter on.");
  }
  while (idList.Count < 5) { idList.Add(-1); }  // -1 is an impossible value
  return ExecuteQuery<PublishDate>(getValuesInListSQL, 
               origCount,   
               idList[0], idList[1], idList[2], idList[3], idList[4]);

基本上，如果count为0，那么就没有过滤器，所有东西都会通过。如果计数高于0，则该值必须在列表中，但列表已被填充为5个不可能的值(因此SQL仍然有意义)

有时蹩脚的解决方案是唯一真正有效的。

    create FUNCTION [dbo].[ConvertStringToList]


      (@str VARCHAR (MAX), @delimeter CHAR (1))
        RETURNS 
        @result TABLE (
            [ID] INT NULL)
    AS
    BEG

IN

    DECLARE @x XML 
    SET @x = '<t>' + REPLACE(@str, @delimeter, '</t><t>') + '</t>'

    INSERT INTO @result
    SELECT DISTINCT x.i.value('.', 'int') AS token
    FROM @x.nodes('//t') x(i)
    ORDER BY 1

RETURN
END

——你的查询

select * from table where id in ([dbo].[ConvertStringToList(YOUR comma separated string ,',')])

步骤1:-

string[] Ids = new string[] { "3", "6", "14" };
string IdsSP = string.Format("'|{0}|'", string.Join("|", Ids));

步骤2:-

@CurrentShipmentStatusIdArray [nvarchar](255) = NULL

步骤3:-

Where @CurrentShipmentStatusIdArray is null or @CurrentShipmentStatusIdArray LIKE '%|' + convert(nvarchar,Shipments.CurrentShipmentStatusId) + '|%'

or

Where @CurrentShipmentStatusIdArray is null or @CurrentShipmentStatusIdArray LIKE '%|' + Shipments.CurrentShipmentStatusId+ '|%'