将临时表传递给EXEC sp_executesql

Question

如何将临时表(@table(传递给EXEC sp_executesql@query

    set @query = 'SELECT GsName, ' + @cols + ' from 
        (
            select GSName, [THour], NumOfTransactions
            from @table
       ) x
        pivot 
        (
             max([NumOfTransactions])
            for [THour] in (' + @cols + ')
        ) p '

Answer 1

这里不是临时表，而是表值参数。

表值参数是使用用户定义的表声明的类型。可以使用表值参数发送多行数据到Transact-SQL语句或例程，例如存储的过程或函数，而不创建临时表或多个参数。

sp_executesql不支持表值参数，但它们必须是声明的类型。

-- So, first we must declare User-Defined Table Type 
CREATE TYPE udtYB_Test AS TABLE(GSName nvarchar(100), THour time, NumOfTransactions int);
GO
-- Now we can create Table-Valued Parameter
Declare @table udtYB_Test;
-- And store there some data
Insert Into @table (GSName, THour, NumOfTransactions)
Values ('Sample', SYSUTCDATETIME(), 1);
-- Just for the reference
Select * From @table;
-- To pass variable to sp_executesql we need parameters definition
DECLARE @ParmDefinition nvarchar(500) = N'@table udtYB_Test READONLY';
-- Please note: table-valued parameter must be READONLY
-- Here I use simplified query for demonstration only
DECLARE @query nvarchar(500) = 'SELECT * FROM @table';
-- and the result should be identical to the reference above
EXECUTE sp_executesql @query, @ParmDefinition, @table = @table;
-- User-Defined Table Type cleanup
DROP TYPE udtYB_Test;
GO

在大多数实际情况下，使用临时表要容易得多：

Create Table #table (GSName nvarchar(100), THour time, NumOfTransactions int);
Insert Into #table (GSName, THour, NumOfTransactions) Values ('Sample', SYSUTCDATETIME(), 1);
Select * From #table;
DECLARE @query nvarchar(500) = 'SELECT * FROM #table';
EXECUTE sp_executesql @query;
Drop Table #table;