使用动态列名SQL Server加入

Question

I have a table which can output any number of different columns (from 'Level1' to 'Level'N).

I need to perform a left join on each of these dynamic columns against a CTE

I have written the following script but keep getting this error:

Msg 102, Level 15, State 1, Line 15 Incorrect syntax near '10'.

To troubleshoot, I have tried removing the each of the variables in the CTE with no luck.

Any help would be much appreciated!

DECLARE @rel varchar(4) = CAST('X112' AS varchar(4))
DECLARE @todaysdate date = CONVERT(date,GETDATE())

--create cte

DECLARE @sqltext varchar(MAX) =



' WITH CTE AS
(
SELECT
                 ID 
            ,STARTDATE 
            ,ENDDATE 
            ,NEWID             

FROM Tbl

WHERE TYPE = ''' + @rel + '''
AND ENDDATE >= ' + CAST(@todaysdate AS varchar(30)) +' AND STARTDATE <= ' + CAST(@todaysdate AS varchar(30)) +'
)

SELECT ID, NEWID, Level';

--find max lvl, convert to str

DECLARE @counter int = (SELECT MAX(lvl) FROM tbl2)
DECLARE @counterstring varchar(3)

SET @counterstring = CAST(@counter AS varchar(3))

WHILE @counter != 0 

BEGIN

        SET @sqltext = @sqltext + @counterstring + ' INTO tbl3 '

                             + ' FROM tbl2 a '
                             + ' LEFT JOIN CTE c ON a.Level' + @counterstring + ' = c.NEWID'

        SET @counter = @counter - 1


END

EXEC(@sqltext)

--edited version
DECLARE @rel varchar(4) = CAST('X112' AS varchar(4))
DECLARE @todaysdate date = CONVERT(date,GETDATE())

DECLARE @sqltext varchar(MAX) =

' WITH CTE AS
(
SELECT
                 ID
            ,STARTDATE 
            ,ENDDATE AS mgmt_ENDDA
            ,NEWID

FROM tbl 

WHERE SUBTY = ''' + @rel + '''
AND ENDDATE >= ' + CAST(@todaysdate AS varchar(30)) +' AND STARTDATE <= ' + CAST(@todaysdate AS varchar(30)) +'
)

INSERT INTO tbl3

SELECT ID, NEWID, Level';

DECLARE @counter int = (SELECT MAX(lvl) FROM tbl2)
DECLARE @counterstring varchar(3)


WHILE @counter != 0 

BEGIN

        SET @counterstring = CAST(@counter AS varchar(3))

        SET @sqltext = @sqltext + @counterstring 
                                + ' FROM tbl2 a '
                                + ' LEFT JOIN CTE c ON a.Level' + @counterstring + ' = c.NEWID'
        SET @counter = @counter - 1


END

EXEC(@sqltext)

Answer 1

Since select * into query creates a new table each time, I am assuming that you are trying to create 'n' number of tables for 'n' number of levels, with the result obtained by joining with nth column. I have 2 suggestions for you

1. Bring the select query within the while loop and append ';' at the end of the loop to split select queries.
2. instead of INTO tbl3 use INTO tbl + @counterstring as select * into will create new table

Hope this helps you

Answer 2

Can you change it like this and try again?

--edited version
DECLARE @rel varchar(4) = CAST('A012' AS varchar(4))
DECLARE @todaysdate date = CONVERT(date,GETDATE())

DECLARE @sqltext varchar(MAX) =

' WITH CTE AS
(
SELECT
                 ID
            ,STARTDATE 
            ,ENDDATE AS mgmt_ENDDA
            ,NEWID

FROM tbl 

WHERE SUBTY = ''' + @rel + '''
AND ENDDATE >= ' + CAST(@todaysdate AS varchar(30)) +' AND STARTDATE <= ' + CAST(@todaysdate AS varchar(30)) +'
)

INSERT INTO tbl3';

DECLARE @counter int = (SELECT MAX(lvl) FROM tbl2)
DECLARE @counterstring varchar(3)


WHILE @counter != 0 

BEGIN

        SET @counterstring = CAST(@counter AS varchar(3))

        SET @sqltext = @sqltext + CHAR(10) +'SELECT ID, NEWID, Level'+@counterstring

        SET @sqltext = @sqltext + ' FROM tbl2 a '
                                + ' LEFT JOIN CTE c ON a.Level' + @counterstring + ' = c.NEWID'

        SET @counter = @counter - 1

        IF @counter <> 0
            SET @sqltext = @sqltext + CHAR(10) + ' UNION '


END

EXEC(@sqltext)

You can try 'UNION ALL' instead of 'UNION' if you dont want to get rid of duplicate data. Hope this helps