Executing cte expression in a dynamic sql

Question

I have the following cte expression which I am try to run in a dynamic sql but I am getting invalid identifiers error in it:

DECLARE @t TABLE ( ID INT, V float, D DATE )

INSERT  INTO @t
VALUES  ( 1, 1.2, '2014-01-01' ),
        ( 1, 1.33, '2014-01-02' ),
        ( 1, 1.33, '2014-01-03' ),
        ( 1, 7, '2014-01-04' ),
        ( 2, 5, '2014-01-04' ),
        ( 2, 8, '2014-01-10' ),
        ( 2, 11, '2014-01-05' );

DECLARE @DealClauseString nvarchar(max)
SET @DealClauseString =';WITH    filter
          AS ( SELECT   ID ,
                        D ,
                        V ,
                        ROW_NUMBER() OVER ( PARTITION BY ID ORDER BY D DESC ) AS RN
               FROM     @t where id =1
             ),
        cte
          AS ( SELECT   ID ,
                        D ,
                        V ,
                        MIN(D) OVER ( PARTITION BY ID ORDER BY D ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING ) AS Min ,
                        MAX(D) OVER ( PARTITION BY ID ORDER BY D ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING ) AS Max
               FROM     filter
               WHERE    RN <= 2
             )
    SELECT  c1.ID ,
            c2.V - c1.V AS V
    FROM    cte c1
            JOIN cte c2 ON c1.ID = c2.ID AND c1.D < c2.D
    WHERE   ( c1.D = c1.MIN OR c1.D = c1.MAX ) 
            AND ( c2.D = c2.MIN OR c2.D = c2.MAX ) '

exec @DealClauseString

Any suggestions?

Also I was going to run this cte expression in a while loop. Are there any performance issue running cte expression in a loop?

Answer 1

Firstly, you can't use a table variable with dynamic sql, so you should use a #temp table instead, although this might just be relevant to your example code.

Secondly, if you are using dynamic sql, you either need to place the variable @DealClauseString in brackets or use sp_executesql, otherwise SQL Server assumes that you're calling a stored procedure.

CREATE TABLE #t ( ID INT, V FLOAT, D DATE )

INSERT  INTO #t
VALUES  ( 1, 1.2, '2014-01-01' ),
        ( 1, 1.33, '2014-01-02' ),
        ( 1, 1.33, '2014-01-03' ),
        ( 1, 7, '2014-01-04' ),
        ( 2, 5, '2014-01-04' ),
        ( 2, 8, '2014-01-10' ),
        ( 2, 11, '2014-01-05' );

DECLARE @DealClauseString NVARCHAR(MAX)
SET @DealClauseString = ';WITH    filter
          AS ( SELECT   ID ,
                        D ,
                        V ,
                        ROW_NUMBER() OVER ( PARTITION BY ID ORDER BY D DESC ) AS RN
               FROM     #t where id =1
             ),
        cte
          AS ( SELECT   ID ,
                        D ,
                        V ,
                        MIN(D) OVER ( PARTITION BY ID ORDER BY D ROWS 
                                      BETWEEN UNBOUNDED PRECEDING 
                                      AND UNBOUNDED FOLLOWING ) AS Min ,
                        MAX(D) OVER ( PARTITION BY ID ORDER BY D ROWS 
                                      BETWEEN UNBOUNDED PRECEDING AND 
                                      UNBOUNDED FOLLOWING ) AS Max
               FROM     filter
               WHERE    RN <= 2
             )
    SELECT  c1.ID ,
            c2.V - c1.V AS V
    FROM    cte c1
            JOIN cte c2 ON c1.ID = c2.ID AND c1.D < c2.D
    WHERE   ( c1.D = c1.MIN OR c1.D = c1.MAX ) 
            AND ( c2.D = c2.MIN OR c2.D = c2.MAX ) '

EXEC (@DealClauseString)

Results:

ID  V
1   5.67