mysql lenght() and char_length not working for longer texts

 a     int  .
 b     Text .

i want restrict my text column 'b' to throw message on lenght greater than 32766. But CHAR_LENGHT() is not working for such a large texts. here is my procedure. Any ideas? DELIMITER $$
CREATE TRIGGER `ALTER_STRINGVALUE` BEFORE INSERT ON `sample` FOR EACH ROW
BEGIN
    IF CHAR_LENGTH ( NEW.b ) > 32766 THEN

        SIGNAL SQLSTATE '02000' SET MESSAGE_TEXT = 'check constraint on Attributes.stringValue failed';     END IF;
END$$
DELIMITER ; Thanks,
Manoj Received on Thu Jul 02 2015 - 07:15:29 CEST