sql - Obtaining counts for two different conditions -


suppose have table states follows:

create table states (id int4 unique not null, state int4 not null);

i want number of rows in table state 1, , number of rows in table state 2. doing in 2 separate queries straightforward:

select count(*) states state = 1; select count(*) states state = 2;

but seems silly go through whole table twice. can think of clever trick allow me same information in single statement , going through table once?

select     count((state = 1)::integer or null) state_1,     count((state = 2)::integer or null) state_2 states

or

select     sum((state = 1)::integer) state_1,     sum((state = 2)::integer) state_2 states

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