List primary keys for all tables - Postgresql

Question

Is there a query that will do that?

I found some queries that can do this for one table, but I wasn't able to modify it so I can see:

tablename | column | type

Answer 1

Something like this:

select tc.table_schema, tc.table_name, kc.column_name
from 
    information_schema.table_constraints tc
    join information_schema.key_column_usage kc 
        on kc.table_name = tc.table_name and kc.table_schema = tc.table_schema
where 
    tc.constraint_type = 'PRIMARY KEY'
    and kc.position_in_unique_constraint is not null
order by tc.table_schema,
         tc.table_name,
         kc.position_in_unique_constraint;

Answer 2

This is more accurate answer:

select tc.table_schema, tc.table_name, kc.column_name 
from  
    information_schema.table_constraints tc,  
    information_schema.key_column_usage kc  
where 
    tc.constraint_type = 'PRIMARY KEY' 
    and kc.table_name = tc.table_name and kc.table_schema = tc.table_schema
    and kc.constraint_name = tc.constraint_name
order by 1, 2;

You missed the and kc.constraint_name = tc.constraint_name part, so it lists all constraints.