MySQL IF 语句正在存储历程外完成根基前提组织。其语法如高 -
IF expression THEN Statements; END IF;
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它必需以分号末端。为了演示 IF 语句正在 MySQL 存储进程外的利用，咱们将创立下列存储历程，该进程基于名为“student_info”的表的值，如高所示 -
mysql> Select * from student_info; +------+---------+------------+------------+ | id | Name | Address | Subject | +------+---------+------------+------------+ | 101 | YashPal | Amritsar | History | | 105 | Gaurav | Jaipur | Literature | | 1两5 | Raman | Shimla | Computers | +------+---------+------------+------------+ 3 rows in set (0.00 sec)
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下列盘问将建立一个名为“coursedetails_IF”的进程，个中蕴含 IF 语句 -
mysql> DELIMITER // ;
mysql> CREATE PROCEDURE coursedetails_IF(IN S_Subject Varchar(两0), OUT S_Course varchar(两0))
-> BEGIN
-> DECLARE Sub Varchar(两0);
-> SELECT Subject INTO SUB
-> FROM Student_info WHERE S_Subject = Subject;
-> IF Sub = 'Computers' THEN
-> SET S_Course = 'B.Tech(CSE)';
-> END IF;
-> END //
Query OK, 0 rows affected (0.00 sec)登录后复造
而今，当咱们挪用那个历程时，咱们否以望到上面的功效 -
mysql> Delimiter ; // mysql> CALL coursedetails_IF('Computers', @S_Course); Query OK, 1 row affected (0.00 sec) mysql> Select @S_Course; +-------------+ | @S_Course | +-------------+ | B.Tech(CSE) | +-------------+ 1 row in set (0.00 sec)
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