How to add columns in select list SQL which are rows of other table : SQL Server 2008

Question

I have a scenario where I need help. I have a table from where I'm pulling Max data group by ID like below.

select ID, max(basic) as B, max(hra) as H
from #temp
group by ID

I have another table (only one column) where I have certain values. Number of rows or data of this table is dynamic. X and Y are just random data. There could be many rows with any varchar data.

select * from #dummy

Now I need rows of #dummy table as columns of #temp like below.

Earlier I was thinking of pivoting but it won't work as there is no relation between these two tables. Any help, TIA.

Answer 1

With a query like this you can create a "column list" with empty entries and create a dynamic SQL Statement. This you execute with EXEC :

DECLARE @addColumns VARCHAR(MAX)=
    (
        SELECT ','''' AS ' + Name
        FROM #dummy
        FOR XML PATH('')
    );

DECLARE @cmd VARCHAR(MAX)=
'SELECT ID, MAX(basic) as B, MAX(hra) as H ' + @addColumns + ' FROM #temp group by ID;'

EXEC (@cmd);

btw: The statement created will look like this:

SELECT ID, MAX(basic) as B, MAX(hra) as H ,'' AS x,'' AS y FROM #temp group by ID;

EDIT2: If you want to add these columns to some table permanently (to add data later) you could use the same approach:

DECLARE @addColumns VARCHAR(MAX)=
STUFF(  (
        SELECT ',' + Name + ' VARCHAR(100) NULL'
        FROM @dummy
        FOR XML PATH('')
    ),1,1,'');

DECLARE @cmd VARCHAR(MAX)=
'ALTER TABLE SomeTable ADD ' + @addColumns +';'

The statement would look like:

ALTER TABLE SomeTable ADD x VARCHAR(100) NULL,y VARCHAR(100) NULL;

Answer 2

this request is sick but i think cursor can do something with it.

 DECLARE @SQLString varchar(100),@new_column varchar(10)
 DECLARE dummy_cursor CURSOR FOR
    SELECT Name FROM dummy
  OPEN dummy_cursor
   FETCH NEXT FROM dummy_cursor into @new_column
  WHILE @@FETCH_STATUS = 0
BEGIN
  SET @SQLString =
 N'Alter TABLE temp ADD @new_column varchar(10)'
 EXECUTE sp_executesql @SQLString;
FETCH NEXT FROM dummy_cursor
END
CLOSE dummy_cursor
DEALLOCATE dummy_cursor