Re: how quick query can be

[Julia Sats]

update (select b.b2 from b where b.b1 = a.a1) set a2 = b2

Ok, now correct.
Can you propose something quicker now ?

<sy******@yahoo.comwrote in message
news:a1**************************@posting.google.c om...

"Julia Sats" <ju********@sympatico.cawrote in message

news:<ij******************@news20.bellglobal.com>. ..

I have two tables A(a1 number, a2 number) and B(b1 number, b2 number)
a.a1 and b.b1 are join columns .
I need to update values of a2 by values of b2.

we can use such update quere
update A set a2 = (select b.b2 from b where b.b1 = a.a1)

Can you propose something quicker ?

Thanks

Switch to a different database. Your query is incorrect too.

Sybrand Bakker
Senior Oracle DBA

[Yak]

"Julia Sats" <ju********@sympatico.cawrote in message news:<jt******************@news20.bellglobal.com>. ..

update (select b.b2 from b where b.b1 = a.a1) set a2 = b2

Ok, now correct.
Can you propose something quicker now ?

I can not see any sense in what you wan't to do, can you be more
specific ?

Do you just want to duplicate your table ?

Drop Table A
Create Table A as Select * from B

or do you have two tabels that should have the same data after every
change ? Then use a trigger on table A wich also changes table B

[Mike]

mo************@gmx.de (Yak) wrote in message news:<d2**************************@posting.google. com>...

"Julia Sats" <ju********@sympatico.cawrote in message news:<jt******************@news20.bellglobal.com>. ..

update (select b.b2 from b where b.b1 = a.a1) set a2 = b2

Ok, now correct.
Can you propose something quicker now ?

I can not see any sense in what you wan't to do, can you be more
specific ?

Do you just want to duplicate your table ?

Drop Table A
Create Table A as Select * from B

or do you have two tabels that should have the same data after every
change ? Then use a trigger on table A wich also changes table B

Tables A and B do not contain only by 2 fields each. At this case drop
table A and create it again as select from B do not work. At this case
has to be updated only one column without change other data.
BTW select count(*) from A and select count(*) from B can be
different.