does anyone knows if it helps to write
where...
if rownum < 2
in the exists - sub-query?
akarb_at_xinfo.dk
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Remco Blaakmeer wrote in message <85b7pe$95k$1_at_rd1936.quicknet.nl>...
>In article <85ad31$jeh$1_at_news.netvision.net.il>,
> "Maoz Mussel" <maoz_at_mindcti.com> writes:
>> What is the fastest method to check whether ANY record satesfy the
>> WHERE clause? For example, the following query:
>> SELECT COUNT (*) FROM tableX
>> WHERE ...
>> May require full table scan in order to return number of records with the
>> specified criteria. Same with any MIN function usage, while all I want is
>> a boolean value specifying whether any record exist, i.e. one that will
>> stop execution once the first record is found.
>
>SELECT 'yes, a record satisfies the WHERE clause'
>FROM dual
>WHERE EXISTS ( SELECT 'x' FROM tablea WHERE ... )
>
>The EXISTS clause will return TRUE at the first row returned from the
>subquery. No more than one row will be fetched from the subquery.
>
>Remco
>--
>rd1936: 12:55am up 1 day, 5:34, 8 users, load average: 2.54, 2.33, 2.33
Received on Mon Jan 10 2000 - 14:01:34 CST
