Sub select.. - Mailing list pgsql-sql

Hi,

I would like to know if ther is a way of doing something like this :

select max(col1) from (select count(*) as col1 from table1 where index_field
= 3 group by day);

table1 loking like :

day    |   index_field   | ...
-------------------------------------
1                1
1                1
1                3
1                3
2                3
3                1
3                3



Finally, I only want to know the maximum count(*) value grouped by day

my sub query should return me :

col1
-------
2      (for day 1)
1       (for day 2)
1       (for day 3)

So, Max(col1) would return me " 2 "

but... imbriqued select doesn't seems to work in 6.5.3....

Any suggestions?

/fb