Tutorial :Dynamic SQL results into temp table in SQL Stored procedure



Question:

The code is as follows:

ALTER PROCEDURE dbo.pdpd_DynamicCall   @SQLString varchar(4096) = null    AS    Begin        create TABLE #T1 ( column_1 varchar(10) , column_2 varchar(100) )        insert into #T1           execute ('execute ' + @SQLString )        select * from #T1     End  

The problem is that I want to call different procedures that can give back different columns. Therefore I would have to define the table #T1 generically. But I don't know how.

Can anyone help me on this problem?


Solution:1

Try:

SELECT into #T1 execute ('execute ' + @SQLString )  

And this smells real bad like an sql injection vulnerability.


correction (per @CarpeDiem's comment):

INSERT into #T1 execute ('execute ' + @SQLString )  

also, omit the 'execute' if the sql string is something other than a procedure


Solution:2

You can define a table dynamically just as you are inserting into it dynamically, but the problem is with the scope of temp tables. For example, this code:

DECLARE @sql varchar(max)  SET @sql = 'CREATE TABLE #T1 (Col1 varchar(20))'  EXEC(@sql)  INSERT INTO #T1 (Col1) VALUES ('This will not work.')  SELECT * FROM #T1  

will return with the error "Invalid object name '#T1'." This is because the temp table #T1 is created at a "lower level" than the block of executing code. In order to fix, use a global temp table:

DECLARE @sql varchar(max)  SET @sql = 'CREATE TABLE ##T1 (Col1 varchar(20))'  EXEC(@sql)  INSERT INTO ##T1 (Col1) VALUES ('This will work.')  SELECT * FROM ##T1  

Hope this helps, Jesse


Solution:3

Be careful of a global temp table solution as this may fail if two users use the same routine at the same time as a global temp table can be seen by all users...


Solution:4

create a global temp table with a GUID in the name dynamically. Then you can work with it in your code, via dyn sql, without worry that another process calling same sproc will use it. This is useful when you dont know what to expect from the underlying selected table each time it runs so you cannot created a temp table explicitly beforehand. ie - you need to use SELECT * INTO syntax

DECLARE @TmpGlobalTable varchar(255) = 'SomeText_' + convert(varchar(36),NEWID())    -- select @TmpGlobalTable     -- build query      SET @Sql =           'SELECT * INTO [##' + @TmpGlobalTable + '] FROM SomeTable'  EXEC (@Sql)  EXEC ('SELECT * FROM [##' + @TmpGlobalTable + '] ')  EXEC ('DROP TABLE [##' + @TmpGlobalTable + ']')  PRINT 'Dropped Table ' + @TmpGlobalTable   


Solution:5

INSERT INTO #TempTable  EXEC(@SelectStatement)  


Solution:6

Not sure if I understand well, but maybe you could form the CREATE statement inside a string, then execute that String? That way you could add as many columns as you want.


Solution:7

DECLARE @EmpGroup INT =3 ,          @IsActive BIT=1    DECLARE @tblEmpMaster AS TABLE          (EmpCode VARCHAR(20),EmpName VARCHAR(50),EmpAddress VARCHAR(500))    INSERT INTO @tblEmpMaster EXECUTE SPGetEmpList @EmpGroup,@IsActive    SELECT * FROM @tblEmpMaster  


Solution:8

CREATE PROCEDURE dbo.pdpd_DynamicCall   AS  DECLARE @SQLString_2 NVARCHAR(4000)  SET NOCOUNT ON  Begin      --- Create global temp table      CREATE TABLE ##T1 ( column_1 varchar(10) , column_2 varchar(100) )        SELECT @SQLString_2 = 'INSERT INTO ##T1( column_1, column_2) SELECT column_1 = "123", column_2 = "MUHAMMAD IMRON"'      SELECT @SQLString_2 = REPLACE(@SQLString_2, '"', '''')        EXEC SP_EXECUTESQL @SQLString_2        --- Test Display records      SELECT * FROM ##T1        --- Drop global temp table       IF OBJECT_ID('tempdb..##T1','u') IS NOT NULL      DROP TABLE ##T1  End  

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