TSQL Define Temp Table (or table variable) Without Defining Schema?

Jeff picture Jeff · Mar 27, 2009 · Viewed 93.7k times · Source

Is there a way to define a temp table without defining it's schema up front?

Answer

ElHaix picture ElHaix · Jan 29, 2010

Actually using a table VARIABLE, an in-memory table, is the optimal way to go. The #table creates a table in temp db, and ##table is global - both with disk hits. Consider the slow-down/hit experienced with the number of transactions.

CREATE PROCEDURE [dbo].[GetAccounts] 
    @AccountID BIGINT,
    @Result INT OUT,
    @ErrorMessage VARCHAR(255) OUT
AS
BEGIN
    SET NOCOUNT ON;
    SET @Result = 0
    SET @ErrorMessage = ''

    DECLARE @tmp_Accounts TABLE (
                                                AccountId BIGINT,
AccountName VARCHAR(50),
...
)

INSERT INTO @tmp_Accounts ([AccountId], [AccountName]...
)
SELECT AccountID, AccountName
FROM Accounts
WHERE  ...


    IF @@Rowcount = 0
        BEGIN
            SET @ErrorMessage = 'No accounts found.'
            SET @Result = 0

            RETURN @Result
        END
    ELSE
        BEGIN
            SET @Result = 1

            SELECT *
            FROM @tmp_Accounts
        END 

Note the way you insert into this temp table.

The down-side of this is that it may take a bit longer to write, as you have to define your table variable.

I'd also recommend SQL Prompt for Query Analyzer by RedGate.