[英]Update table based on column in another table
UPDATE bad_table,good_table
SET bad_table.post_content = good_table.post_content
WHERE bad_table.post_type = 'post' AND
bad_table.post_date = good_table.post_date
This is my code for getting one whole column from one table to another, based on a date value, which I found is unique for this case. 这是我的代码,用于根据日期值从一个表到另一个表获取一个完整列,我发现这个案例是唯一的。 However, I get nothing.
但是,我一无所获。
If I select this, like so: 如果我选择这个,就像这样:
SELECT * FROM bad_table,good_table
WHERE bad_table.post_type = 'post' AND
bad_table.post_date = good_table.post_date
...I get all the rows I would expect. ...我得到了我期望的所有行。 What am I doing wrong?
我究竟做错了什么?
Assuming there could be multiple entries in good_table that are not posts, you need to refine your join condition to only select 'posts' 假设good_table中可能有多个不是帖子的条目,您需要优化您的加入条件以仅选择“帖子”
update bad_table
inner join good_table on bad_table.post_date = good_table.post_date
and bad_table.post_type = good_table.post_type
set bad_table.post_content = good_table.post_content
where bad_table.post_type = 'post'
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