mysql - SQL 查询中的错误

Question

我需要有人帮我找出我的 sql 查询中的错误：

CREATE PROCEDURE confirm(IN bookingID INT, OUT status VARCHAR(40))
BEGIN
DECLARE numberOfPass INT;
DECLARE contactStatus VARCHAR(30);
SET numberOfPass = (SELECT count(*) FROM passenger WHERE passenger.Booking = bookingID);
SET contactStatus = (SELECT contact FROM booking WHERE booking.Id = bookingID);
IF numberOfPass <> (SELECT numberOfSeats FROM booking WHERE booking.Id  = bookingID)) THEN SET status = "Passenger information missing";
ELSE IF ISNULL(contactStatus) THEN SET status ="Contact missing for booking";
ELSE SET status = "OK";
END IF;
END; 

我收到以下错误消息：

ERROR 1064 (42000)：您的 SQL 语法有错误；检查与您的 MySQL 服务器版本相对应的手册，以在 ') THEN SET status = "Passenger information missing" 附近使用正确的语法；ELSE IF ISNULL(contactStatu' 在第 7 行

可能是什么错误？

提前致谢。

Answer 1

你有一个额外的括号

IF numberOfPass <> (SELECT numberOfSeats FROM booking WHERE booking.Id  = bookingID))

Answer 2

• 利用ELSEIF
• 去掉多余的括号

完整的查询，

DELIMITER $$
CREATE PROCEDURE confirm(IN bookingID INT, OUT status VARCHAR(40))
BEGIN
    DECLARE numberOfPass INT;
    DECLARE contactStatus VARCHAR(30);
    SET numberOfPass = (SELECT count(*) FROM passenger WHERE passenger.Booking = bookingID);
    SET contactStatus = (SELECT contact FROM booking WHERE booking.Id = bookingID);
    IF numberOfPass <> (SELECT numberOfSeats FROM booking WHERE booking.Id  = bookingID) THEN 
        SET status = "Passenger information missing";
    ELSEIF ISNULL(contactStatus) THEN 
        SET status ="Contact missing for booking";
    ELSE 
        SET status = "OK";
    END IF;
END $$
DELIMITER ;

• 请参阅 IF 语法^{MySQL 文档}

Answer 3

额外的）在你的代码中......

                                                                                    !!!
 IF numberOfPass <> (SELECT numberOfSeats FROM booking WHERE booking.Id  = bookingID))