MySQL的更新 - MAX（）GROUP BY

Question

如何更改：

SELECT user.postcode, max(postcode.postcode) as postcode 
FROM user 
INNER JOIN postcode ON user.postcode LIKE CONCAT(postcode.postcode, "%") 
GROUP BY user.postcode 

到UPDATE相似？

UPDATE user 
INNER JOIN postcode ON user.postcode LIKE CONCAT(postcode.postcode, "%") 
SET user.lat = postcode.lat, user.lng = postcode.lng 

我无法工作，如何在MAX（）和GROUP BY因素

回答

下面是我的@ceteras代码版本。它很棒！

DROP TABLE IF EXISTS tmp; 
CREATE TABLE tmp AS 
SELECT user.user_id, max(postcode.postcode) AS postcode, postcode.lat, postcode.lng 
FROM user 
INNER JOIN postcode ON user.postcode LIKE CONCAT(postcode.postcode, "%") 
GROUP BY user.postcode; 
ALTER TABLE tmp ADD PRIMARY KEY(user_id); 

UPDATE user 
INNER JOIN tmp ON user.user_id = tmp.user_id 
SET user.lat1 = tmp.lat, user.lng1 = tmp.lng; 

DROP TABLE tmp; 

Answer 1

这是一次性工作吗？ 如果是的话，试试这个：

drop table if exists tmp; 
create table tmp as 
SELECT user.postcode, max(postcode.postcode) as post_code 
FROM user 
INNER JOIN postcode ON user.postcode LIKE CONCAT(postcode.postcode, "%") 
GROUP BY user.postcode; 
alter table tmp add unique key(postcode, post_code), add key (post_code, postcode); 

UPDATE user 
INNER JOIN tmp ON user.postcode = tmp.postcode 
inner join postcode p on p.postcode = tmp.post_code 
SET user.lat = p.lat, user.lng = p.lng; 

drop table tmp;