mysql 如果不存在

发布于 2024-11-30 05:24:54 字数 306 浏览 1 评论 0原文

我来自 MSSQL，现在使用 Mysql，这可能很简单，但是如何执行 if 不存在语句。谢谢

IF NOT EXISTS(SELECT * from users WHERE Username = spUsername)
    BEGIN
    INSERT into users(ID,Username,Password,Email,Birthdate,DateJoin)
            VALUES(UUID(),spUsername,spPassword,spEmail,spBirthDate,NOW());
    END

原文

I am coming from MSSQL, and now using Mysql, this may be a easy one but how do you execute a
if not exist statement. thanks

IF NOT EXISTS(SELECT * from users WHERE Username = spUsername)
    BEGIN
    INSERT into users(ID,Username,Password,Email,Birthdate,DateJoin)
            VALUES(UUID(),spUsername,spPassword,spEmail,spBirthDate,NOW());
    END

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音盲 2024-12-07 05:24:54

无论如何，我不是数据库专家，但这就是我的做法。

http://www.somethinghitme.com/ 2010/05/06/mysql-stored-procedures-if-not-exists/

    DECLARE SomeId int;
    DECLARE CheckExists int;
    SET CheckExists = 0;  

    SELECT 1 INTO CheckExists from lookup_table WHERE someField = in_SomeParam LIMIT 1;   

    IF (CheckExists > 0) THEN
        SELECT id INTO SomeId FROM lookup_table WHERE someField = in_SomeParam;
    ELSE
        INSERT INTO lookup_table (someField ) VALUES(in_SomeParam);
        SELECT SomeId = LAST_INSERT_ID();
    END IF;

Im not a database expert by any means but this is how I do it.

http://www.somethinghitme.com/2010/05/06/mysql-stored-procedures-if-not-exists/

    DECLARE SomeId int;
    DECLARE CheckExists int;
    SET CheckExists = 0;  

    SELECT 1 INTO CheckExists from lookup_table WHERE someField = in_SomeParam LIMIT 1;   

    IF (CheckExists > 0) THEN
        SELECT id INTO SomeId FROM lookup_table WHERE someField = in_SomeParam;
    ELSE
        INSERT INTO lookup_table (someField ) VALUES(in_SomeParam);
        SELECT SomeId = LAST_INSERT_ID();
    END IF;

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