Обсуждение: select count(*) from : 0 rows or 1 rows ?

discovery=> select count(*) from publications;
count
-----   0
(1 row)
 Does 1 rows is a correct result ?
Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83

Thus spake Oleg Bartunov
> discovery=> select count(*) from publications;
> count
> -----
>     0
> (1 row)
> 
>   Does 1 rows is a correct result ?

Absolutely.  "SELECT COUNT(*)..." always returns exactly one row (well,
assuming that the table exists, of course) so this is correct.  A return
of zero rows would imply that no information was returned but you did
get back information here, the fact that the table is empty.

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> discovery=> select count(*) from publications;
> count
> -----
>     0
> (1 row)
> 
>   Does 1 rows is a correct result ?
> 
>     Oleg

One row is returned, and that row is zero.  It is correct.

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