if expression then statements;else else-statements;end if;
语句必须以分号结尾。
为了演示在 mysql 存储过程中使用 if else 语句，我们创建了以下存储过程：基于名为“student_info”的表的值，如下所示 -
mysql> select * from student_info;+------+---------+------------+------------+| id | name | address | subject |+------+---------+------------+------------+| 101 | yashpal | amritsar | history || 105 | gaurav | jaipur | literature || 125 | raman | shimla | computers |+------+---------+------------+------------+3 rows in set (0.00 sec)
以下查询将创建一个名为“coursedetails_ifelse”的过程，其中包含 if else 语句 -
mysql> delimiter // ;mysql> create procedure coursedetails_ifelse(in s_subject varchar(20), out s_course varchar(50)) -> begin -> declare sub varchar(20); -> select subject into sub -> from student_info where s_subject = subject; -> if sub = 'computers' then -> set s_course = 'b.tech(cse)'; -> else -> set s_course = 'subject not in the table '; -> end if; -> end //query ok, 0 rows affected (0.00 sec)
现在，当我们调用这个过程时，我们可以看到下面的结果 -
mysql> delimiter ; //mysql> call coursedetails_ifelse('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)mysql> call coursedetails_ifelse ('history', @s_course);query ok, 0 rows affected (0.00 sec)mysql> select @s_course;+--------------------------------+| @s_course |+--------------------------------+| subject not in the table |+--------------------------------+1 row in set (0.00 sec)
以上就是mysql if else 语句如何在存储过程中使用？的详细内容。