如何使用加入从选择更新

2021-12-17 00:00:00 join sql-update sql select mysql

如何更新也存在于子查询中的表?我必须分两个阶段完成吗?(创建一个临时表——将选中的数据放入其中,然后更新最终表)

How can I update a table that is also present in a subquery? Do I have to do it in 2 stages? (create a temporary table - put the selected data in it and then update the final table)

我正在尝试使用每个 CTN 的网络标签更新 invoiceLine 表.

I am trying to update the invoiceLine table with the label of the network for each CTN.

最终结果是:

  • 发票行

ctn       network
1234      network1
2345      network2
3456      network1

我有以下表格:

  • 发票行

ctn       network
1234      null
2345      null
3456      null

  • 终端

  • terminal

    ctn       network
    1234      1
    2345      2
    3456      1
    

  • 网络

  • network

    id        label
    1         network1
    2         network2
    

  • 我可以运行一个选择,但我不知道如何通过加入进行更新:

    I can run a select but I'm not sure how to update with a join:

    update invoiceLine 
    inner join terminal on terminal.ctn = invoiceLine.ctn 
    set invoiceLine.network = 
    (
      select network.label 
      from invoiceLine 
      inner join terminal on terminal.ctn = invoiceLine.ctn 
      inner join network on network.id = terminal.network
    ) 
    where invoiceLine.ctn = terminal.ctn
    

    但是 MySQL 抛出一个

    but MySQL throws a

    错误代码:1093.您不能在 FROM 子句中指定要更新的目标表invoiceLine"

    Error Code: 1093. You can't specify target table 'invoiceLine' for update in FROM clause

    推荐答案

    UPDATE invoiceLine
        INNER JOIN terminal
            ON invoiceLine.ctn = terminal.ctn
        INNER JOIN network
            ON terminal.network = network.id
        SET invoiceLine.network = network.label
    

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