无法将 IF/ELSE in MySQL 与 PRINT 语句一起使用

Question

我正在尝试在 MySQL 中的条件为真时打印一些内容。这是我的代码：

BEGIN

UPDATE president
INNER JOIN election ON president.pres_name = election.candidate
SET yrs_serv = yrs_serv + 4
WHERE election.winner_loser_indic = 'W'
AND election.election_year = (SELECT MAX(election_year) FROM election)

BEGIN
IF (yrs_serv > 4) THEN BEGIN PRINT "warning"
END
END

END

当我运行出现这个错误时。

MySQL: #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 'BEGIN IF (yrs_serv > 4) THEN BEGIN PRINT "warning" END END END' at line 7

这是一个过程。我想不通。如果我不尝试使用 IF 语句，代码就可以工作。

Answer 1

首先，update 末尾缺少 ;，然后 IF 不需要 Begin。然后 IF 的结尾由 END IF; 完成只需要一个 Begin .... End 试试下面的代码

BEGIN

UPDATE president
INNER JOIN election ON president.pres_name = election.candidate
SET yrs_serv = yrs_serv + 4
WHERE election.winner_loser_indic = 'W'
AND election.election_year = (SELECT MAX(election_year) FROM election);


IF (yrs_serv > 4) THEN 
 Select "warning"; // PRINT "warning" can be achived by Select
END IF;

END;

无法将 IF/ELSE in MySQL 与 PRINT 语句一起使用

Cant use IF/ELSE in MySQL with PRINT statement

mysql

sql

printing

if-statement