I wasn't sure it made logical sense to allow correlated subqueries in
FROM because the FROM is processed before the WHERE.
---------------------------------------------------------------------------
Hannu Krosing wrote:
> Bruce Momjian kirjutas E, 17.03.2003 kell 20:49:
> > With no one replying on how to do correlated subqueries in FROM for
> > UPDATE,
>
> Correlated subqueries not working in FROM cluse of UPDATE is IMHO a bug,
> so the way to do correlated subqueries in FROM for UPDATE would be to
> fix this bug ;)
>
> All common sense tells me that if I can update set col1=col2 and *not*
> get the value from the first col2 to all col1's then the same should be
> true for this
>
> hannu=# creatre table updtarget(
> hannu(# id int, val text);
> ERROR: parser: parse error at or near "creatre" at character 1
> hannu=# create table updtarget(id int, val text);
> CREATE TABLE
> hannu=# create table updsource(id int, val text);
> CREATE TABLE
> hannu=# insert into updtarget(id) values (1);
> INSERT 16995 1
> hannu=# insert into updtarget(id) values (2);
> INSERT 16996 1
> hannu=# insert into updsource(id,val) values (1,'one');
> INSERT 16997 1
> hannu=# insert into updsource(id,val) values (2,'two');
> INSERT 16998 1
> hannu=# update updtarget set val = src.val
> hannu-# from (select s.val from updsource s
> hannu-# where s.id=updtarget.id) as src
> hannu-# ;
> NOTICE: Adding missing FROM-clause entry in subquery for table
> "updtarget"
> UPDATE 2
> hannu=# select * from updtarget;
> id | val
> ----+-----
> 1 | one
> 2 | one
> (2 rows)
>
> there should be no need to add "missing FROM-clause entry" and the
> result *should* be:
>
> hannu=# select * from updtarget;
> id | val
> ----+-----
> 1 | one
> 2 | two
> (2 rows)
>
> --------------------
> Hannu
>
>
>
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-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
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