Question

    "id"    "type"  "parent"    "country"   "votes" "perCent"
    "1"     "1"     "0"         "US"        "100"       "0"
    "2"     "1"     "0"         "US"        "50"        "0"
    "3"     "100"   "0"         "US"        "150"       "0" ->150 = sum(votes) where type = 1 and country = country
    "4"     "1"     "0"         "SE"        "50"        "0"
    "5"     "1"     "0"         "SE"        "25"        "0"
    "6"     "100"   "0"         "SE"        "75"        "0" ->75 = sum(votes) where type = 1 and country = country

我正在尝试使用各自国家/地区的所有type=100的总计更新type=1。

我一直在努力使用这个SQL，似乎无处可去。基本上，我要做的是更新其中type = 100的投票，其各自国家的类型= 1的总和。我一直试图调整这个，但似乎完全失败了。你能帮忙吗？

UPDATE likes p
JOIN likes h
  ON p.country = h.country
    AND (p.type=1) AND h.type=1
SET p.votes=sum(h.votes) where p.type=100;

Answer 1

UPDATE  tableName a
        INNER JOIN
        (
            SELECT  country, SUM(votes) totalVotes
            FROM    tableName
            WHERE   type = 1
            GROUP   BY country
        ) b ON a.country = b.country
SET     a.votes = b.totalVotes
WHERE   a.type = 100

SQLFiddle Demo

mySql使用行的sum（）更新

1 个答案: