CREATE TABLE #tempA(...)
CREATE TABLE #tempB(...)

------------------------------------


INSERT INTO #tempB
SELECT <some stuff from other tables>
FROM	HeadData

LEFT JOIN ...
LEFT JOIN ...
LEFT JOIN ...


------------------------------------

INSERT INTO #tempA
SELECT	A,B,C,D, ..., AB.*, BB.*
FROM SomeTable STable
LEFT JOIN	#tempB ON  ...
LEFT JOIN ...
LEFT JOIN ...
INNER JOIN ...
LEFT JOIN ...
WHERE BB.Value IS NULL
AND ...
AND ...
AND ...
AND ...
AND ...

------------------------------------------------------------


SET @sql = 'SELECT ' + @FieldList + ' FROM #tempA '
SET @sql = @sql +'GROUP BY ' + @FieldList
EXEC sp_Executesql @sql