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    mysql怎么實現存在就更新不存在就添加數據

    小億
    81
    2024-01-03 15:13:04
    欄目: 編程技術

    可以使用INSERT…ON DUPLICATE KEY UPDATE語句來實現存在就更新不存在就添加數據的操作。

    假設我們有一個表格名為users,包含id、name和age三列,其中id是主鍵?,F在需要根據id來判斷數據是否存在,存在則更新name和age,不存在則添加新數據。

    可以使用以下語句實現:

    INSERT INTO users (id, name, age)
    VALUES (1, 'John', 25)
    ON DUPLICATE KEY UPDATE name = VALUES(name), age = VALUES(age);
    

    在上面的例子中,我們嘗試插入一個id為1的數據,如果該id已經存在,則會更新name和age的值為’John’和25;如果該id不存在,則會插入一條新的數據。

    注意:在使用該語句前,需要為id列添加主鍵約束或唯一索引,以使其具備唯一性。

    0
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