Обсуждение: Query question

I seem to have a problem with a specific query:

The inside query seems to work on it's own:
            select prefix            from john_prefix            where strpos(jpt_test.number,john_prefix.prefix) = '1'
          order by char_length(john_prefix.prefix) desc limit 1
 

but when I execute it with this:

UPDATE    jpt_test
set    number = substring(number from length(john_prefix.prefix)+1)
from    john_prefix
where    prefix in (            select prefix            from john_prefix            where
strpos(jpt_test.number,john_prefix.prefix)= '1'            order by char_length(john_prefix.prefix) desc limit 1    )
;

table contents are as follows

john_prefix table:

prefix
---------
123
234

jpt_test table:

number
-----------
1237999999
0234999999 <<< supposed to have no match
2349999999

Am I missing something here? Any help will be appreciated.

Regards,
JPT

On 01/26/2012 04:00 AM, John Tuliao wrote:
> I seem to have a problem with a specific query:
>
> The inside query seems to work on it's own:
>
> select prefix
> from john_prefix
> where strpos(jpt_test.number,john_prefix.prefix) = '1'
> order by char_length(john_prefix.prefix) desc limit 1
>
> but when I execute it with this:
>
> UPDATE
>     jpt_test
> set
>     number = substring(number from length(john_prefix.prefix)+1)
> from
>     john_prefix
> where
>     prefix in (
>         select prefix
>         from john_prefix
>         where strpos(jpt_test.number,john_prefix.prefix) = '1'
>         order by char_length(john_prefix.prefix) desc limit 1
>     ) ;
>
> table contents are as follows
>
> john_prefix table:
>
> prefix
> ---------
> 123
> 234
>
> jpt_test table:
>
> number
> -----------
> 1237999999
> 0234999999 <<< supposed to have no match
> 2349999999
>
> Am I missing something here? Any help will be appreciated.

I'm going to guess that it's because you didn't use a separate alias for the 
FROM in the correlated subquery.

Doesn't STRPOS() return INTEGER, not TEXT?

-- 
Lew
Honi soit qui mal y pense.
http://upload.wikimedia.org/wikipedia/commons/c/cf/Friz.jpg