Pass temp table to EXEC sp_executesql

Question

How can I pass temp table (@table) to 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

What you have here is not Temporary Table, but a Table-Valued Parameter.

Table-valued parameters are declared by using user-defined table types. You can use table-valued parameters to send multiple rows of data to a Transact-SQL statement or a routine, such as a stored procedure or function, without creating a temporary table or many parameters.

sp_executesql does support table-valued parameters, but they must be of declared type.

-- 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

In most practical cases it is much easier to use a temporary table:

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;