Question : union issue in SQL 2k

when you have more than 2 unions in a statement, there is a restriction of how many columns can be included in the query. is this issue addressed by microsoft and what is the reason for this?

Answer : union issue in SQL 2k

Select Customer ,TrsNo  ,TrsDate        ,Qty
FROM (
     Select Customer ,TrsNo  ,TrsDate        ,Qty,
      rn = row_number() over (partition by Customer order by TrsDate ASC)
     from tbl
) SQ
Where rn=1