Need to fine tune Query ....

Question

Hi...
SELECT
a.id, a.fname, a.lname
FROM
a inner join b ON a.id = b.id
WHERE
a.del_status = 'N' AND a.type = 2
GROUP BY
a.id, a.name, a.lname
if i run this Query it take s one sec
SELECT
a.id, a.fname, a.lname
FROM
a inner join b ON a.id = b.id
WHERE
a.del_status = 'N' AND a.type = 2 and b.status =1
GROUP BY
a.id, a.name, a.lname
if i add status it takes 7 Min
i cant found the reason
this is the explain plan for second query
Operation     Object Name     Rows     Bytes     Cost     Object Node     In/Out     PStart     PStop
SELECT STATEMENT Optimizer Mode=CHOOSE          73           92                     
SORT GROUP BY          73      3 K     92                     
NESTED LOOPS          73      3 K     88                     
TABLE ACCESS FULL     NOTIFY_SOURCE_DETAIL     73      1 K     15                     
TABLE ACCESS BY INDEX ROWID     MEMBER     1      20      1                     
INDEX UNIQUE SCAN     I_MEMBER_2     2                               
Thanks,

Answer 1

Hi
If you have an index on the b.id then Oracle does not have to read the actual data in the first query.
But when you refer to status, then Oracle will have to retrieve the row and check that field.
pls. supply BOTH explain plans
regards
Mette