postgresql - SQL Retrieve rows that have all rows from other table -


i facing issues retrieving data using sql in 1 specific scenario:

suppose have following tables:

  • a (id, attr_a, attr_b);
  • b (id, attr_d, attr_e);
  • c (id_a, id_b);

as can see, table c have fk referencing id table a, , referencing id table c.

i need retrieve table a rows each a row relates every b row.

in real life scenario, assuming a means users, b means privileges, , c many many entity relates users privileges, want users have privileges

select a.* join c on id_a = id group id having count(id) = (select count(*) b)

there no need use subquery because a.id primary key (or unique @ least) column referenced c.id_a.


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