Re: now i'm really confused. insert/update does autocast, where sometimes.

demo=# ALTER TABLE a ADD COLUMN d VARCHAR;
ALTER TABLE
demo=# UPDATE a SET d=current_date;
UPDATE 3
demo=# SELECT * FROM a WHERE d=current_date;
ERROR:  operator does not exist: character varying = date at character 24
HINT:  No operator matches the given name and argument type(s). You 
might need t
o add explicit type casts.
LINE 1: SELECT * FROM a WHERE d=current_date;


so and now think what takes happen in plpgsql functions if you work with 
variables.

DECLARE z INTEGER;

calculations

UPDATE a SET b=z WHERE xyz;

 GET DIAGNOSTICS rows = ROW_COUNT;
 IF rows=0 THEN
 ELSE
    FOR r IN SELECT * FROM a WHERE b=z....
 END IF;



i know that are hypotethical issues but i will show the risk.