Question

我有一个查询，我似乎无法操作在MySQL中的SUM函数中工作：

这就是我想要的：

更新account_seeds AS a   INNER JOIN b AS b ON b.accountID = a.accountID AND a.areaID = b.areaID
  INNER JOIN b_seed AS s ON s.buildingID = b.buildingID
  INNER JOIN seed_class AS c ON c.seedID = s.seedID
  设置a.amount = a.amount + SUM（s.amount）
  在哪里b.status =＆＃39;活跃＆＃39; AND a.seedID = s.seedID

现在它显然不允许我在更新中使用SUM而不将其分开。我已尝试加入选择查询，但无法理解我的想法。基本前提是我有多个建筑物（行），其种子值将增加特定帐户区域中该类型的总种子数。没有总和，它只更新一个具有匹配种子值的建筑物

Answer 1

UPDATE 
    account_seeds AS a 
  INNER JOIN 
    ( SELECT b.accountID, b.areaID, s.seedID
           , SUM(s.amount) AS add_on 
      FROM b AS b 
        INNER JOIN b_seed AS s 
          ON s.buildingID = b.buildingID
        INNER JOIN seed_class AS c 
          ON c.seedID = s.seedID
      WHERE b.status = 'active' 
      GROUP BY b.accountID, b.areaID, s.seedID
    ) AS g
    ON  g.accountID = a.accountID 
    AND g.areaID = a.areaID
    AND g.seedID = a.seedID
SET 
    a.amount = a.amount + g.add_on ;

Answer 2

也许您可以使用嵌套查询：

UPDATE account_seeds AS a 
INNER JOIN b AS b ON b.accountID = a.accountID AND a.areaID = b.areaID
INNER JOIN b_seed AS s ON s.buildingID = b.buildingID
INNER JOIN seed_class AS c ON c.seedID = s.seedID
SET a.amount = a.amount + (SELECT SUM(amount) FROM b_seed)
WHERE b.status='active' AND a.seedID = s.seedID

你能试试吗？

MySQL Update表，其中包含另一个表的和值

2 个答案: