troubleshooting Question

faster sql

Avatar of at999
at999 asked on
Oracle Database
14 Comments3 Solutions353 ViewsLast Modified:
Which one of these two sqls - SQL1 and SQL2 will be faster to execute and why -

SQL1:  
UPDATE mytable1  A SET A.XC  = ( SELECT B.PXC   FROM   mytable2 B WHERE A.PRCLID=B.PRCLID );
 
SQL2:
UPDATE mytable1  A SET A.XC  = ( SELECT B.PXC   FROM   mytable2 B WHERE A.PRCLID=B.PRCLID ) where exists( select c.prclid from mytable1 c, mytable2 d where c.prclid = d.prclid);

Or will it take same time to execute?

Or can you please give me tips how to make the first sql run faster?

thanks a lot
ASKER CERTIFIED SOLUTION
Mark Geerlings
Database Administrator, retired

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