mysql - 创建函数时出现 MYSQL 1064 错误

Question

DELIMITER $$

    CREATE FUNCTION nameOfFunct(intIn int)
    RETURN int
    BEGIN
        DECLARE intOut INT;
        SET intOut = SELECT count(*)
            FROM tableToTakeFrom
            WHERE columToCompareTo = intIn;

        RETURN intOut;
    END;
        $$

DELIMITER;

如果我尝试运行它，我得到的是:

SQL Error (1064): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'RETURN int
BEGIN
DECLARE intOut INT;
SET intOut = select count(' at line 2

Answer 1

解决问题的几个更改:

DELIMITER $$

CREATE FUNCTION nameOfFunct(intIn INT)
-- RETURN INT
RETURNS INT
BEGIN
    DECLARE intOut INT;
    /*SET intOut = SELECT COUNT(*)
        FROM tableToTakeFrom
        WHERE columToCompareTo = intIn;*/
    SET intOut = (SELECT COUNT(*)
        FROM tableToTakeFrom
        WHERE columToCompareTo = intIn);
    RETURN intOut;
END $$

DELIMITER ;