Question

这个MySQL查询抛出错误：

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

我已尝试过所有以前给出的答案，但我的问题仍未解决，请帮忙。

update myTable set total = total+1
where (x_id, y_id) in
(
select x_id, y_id
from xTable join myTable using(x_id)
where (x_code='NA-204' and y_id in (select y_id from yTable where z_id=5))
or (x_code='PS-204' and y_id in (select y_id from yTable where z_id=1))
);

Answer 1

这是一个简单的技巧，但它可能很慢：

update myTable set total = total+1
where (x_id, y_id) in
(
  SELECT * FROM
  (
  select x_id, y_id
  from xTable join myTable using(x_id)
  where (x_code='NA-204' and y_id in (select y_id from yTable where z_id=5))
  or (x_code='PS-204' and y_id in (select y_id from yTable where z_id=1))
  ) s
)

或者您可以使用JOIN：

update
  myTable INNER JOIN (
    select x_id, y_id
    from xTable join myTable using(x_id)
    where (x_code='NA-204' and y_id in (select y_id from yTable where z_id=5))
    or (x_code='PS-204' and y_id in (select y_id from yTable where z_id=1))
  ) s
  ON myTable.x_id=s.x_id
     AND myTable.y_id=s.y_id
set
  myTable.total = myTable.total+1

如果在子查询中使用它，如何更新表

1 个答案: