Steve Crawford wrote on 01.07.2009 00:39:
>> canon=# select count(maf) from gallo.sds_seq_reg_shw
>> canon-# where maf ISNULL;
>>
> I believe count will only count not-null
Correct
SELECT count(some_col)
FROM some_table;
is the same as
SELECT count(*)
FROM some_table
WHERE some_col IS NOT NULL;