NVL(ROW, NULL) = NULL vs ROW IS NULL - Cost efficiency ?
581251Feb 14 2008 — edited Feb 14 2008Hi !
A recent optimization report came back saying that on our more complex queries, the NVL(ROW, NULL) = NULL should be used instead of ROW IS NULL in our WHERE clauses.
For example, in the following WHERE clause using
WHERE (ROW1 = :VARIABLE OR NVL(ROW1, NULL) = NULL)
instead of
WHERE (ROW1 = :VARIABLE OR ROW1 IS NULL)
I have never seen a NVL(ROW, NULL) = NULL statement before and am having difficulty understanding how it could be more efficient.
Could someone please advise me on this ?
Thanks.