Calling a function with a boolean return value inside of a trigger in postgres

Question

I am trying to call a function inside of a trigger in postgres. Basically I have a function, ``` c.check_level(bigint, integer) ``` which returns a boolean value. I would like to call this function inside of a trigger as follows: ``` CREATE OR REPLACE FUNCTION c.check_level_tg() RETURNS trigger AS $BODY$ DECLARE parent_id int8; level int; result bool; begin parent_id := NEW.fk_parent; level := NEW.level; select * from c.check_category_level(parent_id, level) as result; if (result) then return (NEW); else return(NULL); end if; END; $BODY$ LANGUAGE plpgsql VOLATILE COST 100; ALTER FUNCTION c.check_category_level_tg() OWNER TO postgres; ``` When I try to put data in the table on which this trigger resides, I get an error: "ERROR: query has no destination for result data HINT: If you want to discard the results of a SELECT, use PERFORM instead. CONTEXT: PL/pgSQL function". The function c.check_level works properly when run in isolation.

Accepted Answer

Change

```
select * from c.check_category_level(parent_id, level) as result;
```

into:

```
SELECT c.check_category_level(parent_id, level) INTO result;
```

Calling a function with a boolean return value inside of a trigger in postgres

Solution

Problem