ww

DELIMITER //DROP FUNCTION IF EXISTS uniqueChars//CREATE FUNCTION uniqueChars(s TEXT) RETURNS TEXTDETERMINISTICBEGIN        DECLARE output TEXT DEFAULT '';        DECLARE temp CHAR(1);        WHILE s <> ''  DO                SET temp = SUBSTR(s FROM 1 FOR 1);                IF LOCATE(temp, output) = 0 THEN                        SET output = CONCAT(output, temp);                END IF;                SET s = SUBSTR(s FROM 2);        END WHILE;        RETURN output;END//DELIMITER ;