Re: select count(*)

i "discovered" it as a result of typo :)

we usually select expressions without tables
eg select 1+2 ; etc and the results are as expected,
somehow i failed to stretch the analogy to count(*)
which is mostly used over tables or table expression.

thanks anyways.

regds
mallah.

On Wed, Mar 9, 2011 at 11:20 PM, Bill Moran <wmoran(at)potentialtech(dot)com>wrote:

> In response to Rajesh Kumar Mallah <mallah(dot)rajesh(at)gmail(dot)com>:
>
> > Dear List ,
> >
> > if we simply do select count(*) and not specify any table then it gives 1
> > eg:
> >
> > bric=# SELECT count(*) from job ;
> > count
> > -------
> > 2380
> > (1 row)
> >
> > bric=# SELECT count(*) job ;
> > job
> > -----
> > 1
> > (1 row)
> >
> >
> >
> > bric=# SELECT count(*) ;
> > count
> > -------
> > 1
> > (1 row)
> >
> >
> >
> > bric=# SELECT count(*) job_non_exist ;
> > job_non_exist
> > ---------------
> > 1
> > (1 row)
> >
> > bric=# SELECT count(*) jo1b ;
> > jo1b
> > ------
> > 1
> > (1 row)
> >
> > bric=# SELECT count(*) none ;
> > ERROR: syntax error at or near "none"
> > LINE 1: SELECT count(*) none ;
> >
> >
> > I fail to see any progression ?
>
> When you don't specify a FROM clause, you get 1 because it's
> returning 1 row. No matter what you alias the result to, it's not going
> to change the result, unless of course you try to alias it to an SQL
> reserved word, such as "none", without quoting it. Of course, if you
> include the optional AS, it probably makes more sense what's going on:
>
> SELECT count(*) AS jolb;
> SELECT count(*) AS none;
> SELECT count(*) AS "none";
>
> --
> Bill Moran
> http://www.potentialtech.com
> http://people.collaborativefusion.com/~wmoran/
>