Question

如何更新子查询中也存在的表？我需要分2个阶段吗？（创建一个临时表 - 将所选数据放入其中，然后更新最终表）

我正在尝试使用每个CTN的网络标签更新invoiceLine表。

最终结果将是：

invoiceLine

ctn       network
1234      network1
2345      network2
3456      network1

我有以下表格：

invoiceLine

ctn       network
1234      null
2345      null
3456      null

终端

ctn       network
1234      1
2345      2
3456      1

网络

id        label
1         network1
2         network2

我可以运行一个选择，但我不确定如何使用连接进行更新：

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MySQL抛出了

错误代码：1093。您无法在FROM子句
中为更新指定目标表'invoiceLine'

Answer 1

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

Answer 2

UPDATE invoiceLine SET network = (
    SELECT label FROM network WHERE id = (
        SELECT network FROM terminal WHERE terminal.ctn = invoiceLine.ctn
    )
)

如何使用Join更新select

2 个答案: