From: amonotod <[EMAIL PROTECTED]>
> > From: amonotod <[EMAIL PROTECTED]>
> > > From: Hernan Arredondo <[EMAIL PROTECTED]>
> > > Date: 2005/01/24 Mon PM 12:41:56 CST
>
> > FROM THE DOCS!
> > <snip>
> > One alternative method to get a row count for a SELECT is to
> > execute a ``SELECT COUNT(*) FROM ...'' SQL statement with the same
> > ``...'' as your query and then fetch the row count from that.
> > </snip>
>
> I guess I should have pointed out that the part you really need to
> take notice of was the last paragraph, in which it is suggested that
> you run a "select count()" before you run your real query.
>
> One extra piece of advice, it says "select count(*)", but I suggest
> you use just "select count(<first_column>)" instead.
Maybe this depends on the database server, but I do believe count(*)
will be quicker than COUNT(<first_column>) under e.g. MS SQL. Besides
the two do not have to return the same number. COUNT(<forst_column>)
doesn't count the rows in which the first_column is null. Eg this
query returns
5, 4, 3
select count(*), count(foo), count(distinct foo)
from (
select 1 as Foo
union all
select 2
union all
select 1
union all
select 3
union all
select null
) as Tbl
If you want the count of rows, use COUNT(*), if you want the count of
Foos use Count(Foo).
Jenda
===== [EMAIL PROTECTED] === http://Jenda.Krynicky.cz =====
When it comes to wine, women and song, wizards are allowed
to get drunk and croon as much as they like.
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