Re: sql-porting-problem oracle to postgresql with UPDATE/IS NOT NULL

Hello,

Le 28/07/09 14:25, Daryl Richter a écrit :
> 
> On Jul 28, 2009, at 5:58 AM, Gau, Hans-Jürgen wrote:
> 
>> hello list,
>> i have some problems with an sql-statement which runs on oracle but
>> not on postgresql (i want update only if result of SELECT is not
>> empty, the SELECT-queries are identical):
>>
>> UPDATE table1 t1
>>         SET (t1.id) =
>>                 (SELECT h.id FROM table2 t2,table3 t3, table1 t1
>>                 WHERE t3.field = t2.field
>>                         AND t2.id = t1.id
>>                         AND t1.id <> t3.id)
>>         WHERE
>>                 (SELECT h.id FROM table2 t2,table3 t3, table1 t1
>>                         WHERE t3.field = t2.field
>>                                 AND t2.id = t1.id
>>                                 AND t1.id <> t3.id) IS NOT NULL;
>>
> Try this:
> 
> UPDATE table1 t1 [...]
>         WHERE
>             EXISTS (SELECT 1 FROM table2 t2,table3 t3, table1 t1
>                         WHERE t3.field = t2.field
>                                 AND t2.id = t1.id
>                                 AND t1.id <> t3.id
> 
>                 AND h.id IS NOT NULL);
> 

Beyond the solution brought by Daryl Richter, it seems that "h" is an
unbound alias in the original (and also in the suggested) query. Some
clarification would be helpful for further investigation.

Regards.

--
nha / Lyon / France.