问题描述

我看到了以下内容(使用 VALUES 选项):

I've seen the following (using the VALUES option):

$query = "INSERT INTO $table (column-1, column-2, column-3) VALUES ('value-1', 'value-2', 'value-3') ON DUPLICATE KEY UPDATE SET column1 = value1, column2 = value2, column3 = value3, ID=LAST_INSERT_ID(ID)"; 

...但我不知道如何将 ON DUPLICATE KEY UPDATE 添加到我正在使用的内容中:

... but I can't figure how to add ON DUPLICATE KEY UPDATE to what I'm using:

$query = "INSERT INTO $table SET
    column-1 ='value-1',
    column-2 ='value-2',
    column-3 ='value-3'
";

例如:，伪代码

$query = "INSERT INTO $table SET
    column-1 ='value-1',
    column-2 ='value-2',
    column-3 ='value-3'
    ON DUPLICATE KEY UPDATE SET
    column1 = value1,
    column2 = value2,
    column3 = value3,
    $id=LAST_INSERT_ID(id)"; 
    $my_id = mysql_insert_id();
";

我会发现后者更容易阅读.希望澄清一下，在手册中没有找到示例.

I would find the latter easier to read. Would appreciate clarification, didn't find an example in the manual.

干杯

推荐答案

我经常使用 ON DUPLICATE KEY UPDATE.在某些情况下，真正值得使用的是非标准 SQL 扩展.

I've used ON DUPLICATE KEY UPDATE a lot. For some situations it's non-standard SQL extension that's really worth using.

首先，您需要确保有一个唯一的键约束.ON DUPLICATE KEY UPDATE 函数仅在存在唯一密钥违规的情况下才会启动.

First, you need to make sure you have a unique key constraint in place. The ON DUPLICATE KEY UPDATE function only kicks in if there would've been a unique key violation.

这是一种常用的格式:

 $query = "INSERT INTO $table (column1, column2, column3)
 VALUES ('value-1', 'value-2', 'value-3')
 ON DUPLICATE KEY UPDATE
 column1 = values(column1),
 column2 = values(column2),
 column3 = values(column3);"

column1 = values(column1) 表示如果查询没有遇到重复键违规，则使用将插入的值更新 column1."换句话说，它只是意味着将 column1 更新为插入工作时的样子.

column1 = values(column1) means "Update column1 with the value that would have been inserted if the query hadn't hit the duplicate key violation." In other words, it just means update column1 to what it would've been had the insert worked.

查看此代码，您要更新您尝试插入的所有三个列似乎并不正确.哪一列有唯一的约束?

Looking at this code, it doesn't seem correct that you're updating all three of the columns you're trying to insert. Which of the columns has a unique constraint on it?

根据 OP 的问题，根据 mysql insert 语句的SET"格式进行修改.

Modify based on 'SET' format of mysql insert statement per the question from the OP.

基本上要使用ON DUPLICATE KEY UPDATE，您只需像往常一样编写插入语句，但在末尾添加ON DUPLICATE KEY UPDATE 子句.我相信它应该像这样工作:

Basically to use ON DUPLICATE KEY UPDATE, you just write the insert statement as you normally would, but add the ON DUPLICATE KEY UPDATE clause tacked onto the end. I believe it should work like this:

INSERT INTO $table 
    set column1 = 'value-1',
        column2 = 'value-2',
        column3 = 'value-3'
ON DUPLICATE KEY UPDATE
    column1 = values(column1),
    column2 = values(column2),
    column3 = values(column3);

同样，您要插入的列之一必须具有唯一索引(或列的组合).这可能是因为其中一个是主键，也可能是因为表上有唯一索引.

Again, one of the columns you're inserting has to have a unique index (or a combination of the columns). That can be because one of them is the primary key or because there is a unique index on the table.

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