Question

I am trying to update all records in my table. As I read through the records I need to update a column in the current record with a value from the NEXT record in the set. The catch is the updates need to be done in a specified order.

I was thinking of something like this …

Update t1
Set col1 = (select LEAD(col2,1) OVER (ORDER BY col3, col4, col5)
            from t1);

This doesn’t compile but you see what I’m driving at … any ideas ?

… update

This peice does run successfully but writes only NULLS

Update t1 A
Set t1.col1 = (select LEAD(col2,1) OVER (ORDER BY col3, col4, col5)
           from t1 B
           where A.col3 = B.col3 AND
                 A.col4 = B.col4 AND
                 A.col5 = B.col5);

Answer 1

This should do it:

merge into t1
using
(
   select rowid as rid, 
          LEAD(col2,1) OVER (ORDER BY col3, col4, col5) as ld
   from t1
) lv on ( lv.rid = t1.rowid )
when matched then 
  update set col1 = lv.ld;

Not 100% sure if I got the syntax completely right, but as you didn’t supply any testdata, I’ll leave potential syntax errors for you to fix.

You can also replace the usage of rowid with the real primary key columns of your table.