I want to make a function that returns the next value of a primary key based on the table name:
CREATE OR REPLACE FUNCTION next_pk (_table varchar) RETURNS INTEGER AS $$
BEGIN
RETURN EXECUTE 'SELECT COALESCE (MAX (primary_key), 0) + 1 FROM ' || quote_ident (_table) || ' limit 1';
END;
$$ LANGUAGE plpgsql;
select next_pk ('myTable');
But it gives the following error:
ERROR: type "execute" does not exist
LINE 1: SELECT EXECUTE 'SELECT COALESCE (MAX (primary_key), 0) + 1 F...
Any clues ? Thanks.
You need integer variable and 'execute into':
CREATE OR REPLACE FUNCTION next_pk (_table varchar) RETURNS INTEGER AS $$
DECLARE
result integer;
BEGIN
EXECUTE
'SELECT COALESCE (MAX (primary_key), 0) + 1 FROM ' || quote_ident (_table)
INTO result;
RETURN result;
END;
$$ LANGUAGE plpgsql;
select next_pk ('myTable');