如何使用 GROUP BY 从 JOIN 更新

Question

在SELECT查询中

SELECT b.id, MIN(IFNULL(a.views,0)) AS counted 
FROM table1 a JOIN table2 b ON a.id=b.id GROUP BY id 
HAVING counted>0

我怎么能拒绝此查询UPDATE作为

UPDATE b.number = counted

Answer 1

UPDATE table2 AS b1, ( SELECT b.id, MIN(IFNULL(a.views, 0)) AS counted 
                       FROM table1 a 
                       JOIN table2 b ON a.id = b.id 
                       GROUP BY id 
                       HAVING counted > 0 ) AS b2
SET b1.number = b2.counted
WHERE b1.id = b2.id