Re: COUNT and GROUP BY performing strangely
От | Jayadevan M |
---|---|
Тема | Re: COUNT and GROUP BY performing strangely |
Дата | |
Msg-id | CAFS1N4iviBdOuTrC2ad=V6N+WVO=fOYrPFsiLrhL0bkNd8C+og@mail.gmail.com обсуждение исходный текст |
Ответ на | COUNT and GROUP BY performing strangely (James David Smith <james.david.smith@gmail.com>) |
Ответы |
Re: COUNT and GROUP BY performing strangely
|
Список | pgsql-novice |
http://stackoverflow.com/questions/2054235/why-doesnt-postgres-group-by-null-select-counts
says "number of input rows for which the value ofexpression is not null"
On Fri, Oct 25, 2013 at 3:38 PM, James David Smith <james.david.smith@gmail.com> wrote:
Hi everyone,
Any thoughts on the below three queries please?
james_traffic=# SELECT count(*) FROM stage;
count
--------
430991
(1 row)
james_traffic=# SELECT bad_flag, count(bad_flag) FROM stage GROUP BY bad_flag;
bad_flag | count
----------+-------
| 0
1 | 4102
(2 rows)
james_traffic=# SELECT count(bad_flag) FROM stage;
count
-------
4102
(1 row)
I'm confused as to why the second query doesn't return this:
bad_flag | count
--------------+-------
| 426889
1 | 4102
It should count the records surely, even if the field is blank/null ?
Thanks
James
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