java - 是否有类似 IF NOT EXISTS 的命令用于插入值？

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CREATE TABLE IF NOT EXISTS Orari (ID int AUTO_INCREMENT PRIMARY KEY,titolo Char(40), sala int ,giorno char(10),Ora char(10));

INSERT INTO Orari VALUES (null,null,1,'lunedi','16:30'),
    (null,null,1,'lunedi','19:30'),
    (null,null,2,'lunedi','16:30'),
    (null,null,2,'lunedi','19:30'),
    (null,null,1,'martedi','16:30'),
    (null,null,1,'martedi','19:30'),
    (null,null,2,'martedi','16:30'),
    (null,null,2,'martedi','19:30'),
    (null,null,1,'mercoledi','16:30'),
    (null,null,1,'mercoledi','19:30'),
    (null,null,2,'mercoledi','16:30'),
    (null,null,2,'mercoledi','19:30'),
    (null,null,1,'giovedi','16:30'),
    (null,null,1,'giovedi','19:30'),
    (null,null,2,'giovedi','16:30'),
    (null,null,2,'giovedi','19:30'),
    (null,null,1,'venerdi','16:30'),
    (null,null,1,'venerdi','19:30'),
    (null,null,2,'venerdi','16:30'),
    (null,null,2,'venerdi','19:30'),
    (null,null,1,'sabato','16:30'),
    (null,null,1,'sabato','19:30'),
    (null,null,2,'sabato','16:30'),
    (null,null,2,'sabato','19:30'),
    (null,null,1,'domenica','16:30'),
    (null,null,1,'domenica','19:30'),
    (null,null,2,'domenica','16:30'),
    (null,null,2,'domenica','19:30');

我想把它放在我每次按下按钮时都会调用的函数中。

IF NOT EXISTS 用于第一个查询……如果表已经存在，则不会重新创建它。

但是每次我按下按钮时，第二个插入值的查询只会一次又一次地插入。

是否有类似 IF NOT EXISTS 的命令用于插入值？

最佳答案

在 where 子句中尝试 NOT EXISTS 或 EXISTS

关于java - 是否有类似 IF NOT EXISTS 的命令用于插入值？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24148255/