Re: select count(*)
От | Bill Moran |
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Тема | Re: select count(*) |
Дата | |
Msg-id | 20110309125032.20e0f25c.wmoran@potentialtech.com обсуждение исходный текст |
Ответ на | select count(*) (Rajesh Kumar Mallah <mallah.rajesh@gmail.com>) |
Ответы |
Re: select count(*)
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Список | pgsql-general |
In response to Rajesh Kumar Mallah <mallah.rajesh@gmail.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/
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