MYSQL中如何退出外部IF语句

如何退出外部IF语句并继续存储过程

IF (true) THEN

    -- do some work here

    IF (somethingWrong=true) THEN
        -- Exit from the outer IF and continue SP
    END IF;

    -- do some work here
END IF;

---

您可以只测试相反的条件：

如果为（true），则
/*在这里做些工作*/
如果（不是什么问题）那么
/*执行此外部IF块中剩余的操作*/
如果结束；
如果结束；

如果您有多个这样的实例，您可能不想嵌套

IF

块：

IF (true) THEN
    /* do some work here */
    IF (NOT somethingWrong) THEN
        /* do some more work here */
        IF (NOT somethingWrong) THEN
            /* Do whatever is remaining to do in this outer IF block */
        END;
    END IF;
END IF;

SET err = 0
IF (true) THEN
    /* do some work here */
    IF (NOT err)
        /* do some more work here that maybe sets the err variable to some non-zero value */
    END IF;
    IF (NOT err)
        /* do some more work here that maybe sets the err variable non-zero */
    END IF;
    IF (NOT err)
        /* do the remaining work */
    END IF;
END IF;

。。。这可能会嵌套得很深。相反，使用一个变量（检查语法）来跟踪错误情况，并将

IF

s展平。大概是这样的：

IF (true) THEN
    /* do some work here */
    IF (NOT somethingWrong) THEN
        /* do some more work here */
        IF (NOT somethingWrong) THEN
            /* Do whatever is remaining to do in this outer IF block */
        END;
    END IF;
END IF;

SET err = 0
IF (true) THEN
    /* do some work here */
    IF (NOT err)
        /* do some more work here that maybe sets the err variable to some non-zero value */
    END IF;
    IF (NOT err)
        /* do some more work here that maybe sets the err variable non-zero */
    END IF;
    IF (NOT err)
        /* do the remaining work */
    END IF;
END IF;

您甚至可以在其中使用相同原理的一些循环：

IF (true) THEN
    /* do some work here */
    IF (NOT err)
        /* do some more work here that maybe sets the err variable to some non-zero value */
    END IF;
    IF (NOT err)
        /* do some more work here that maybe sets the err variable non-zero */
    END IF;
    WHILE (NOT err AND some_loop_condition) DO
        /* some work that needs to repeat a few times, 
           but should be interrupted when err is non-zero */
    END WHILE
    IF (NOT err)
        /* do the remaining work */
    END IF;
END IF;

---

按照您现在拥有代码的方式，执行将以任何方式退出外部

IF

块，无论内部条件是否为true。你到底在寻找什么？

如果（somethingherre==true），那么MySQL中就不存在
=
，你需要使用
=
来检查equals