Question

使用下表：

"id"    "type"  "parent"    "country"   "votes" "perCent"
"1"     "1"     "0"         "US"        "0"     "0"//Appears as 0, should be 12
"2"     "2"     "1"         "US"        "0"     "0"//Appears as 0, should be 8
"3"     "3"     "2"         "US"        "4"     "0"
"7"     "3"     "2"         "US"        "4"     "0"
"19"    "3"     "1"         "US"        "4"     "0"
"4183"  "10"    "3"         "US"        "2"     "0"
"4184"  "10"    "3"         "US"        "2"     "0"
"4185"  "10"    "7"         "US"        "2"     "0"
"4186"  "10"    "7"         "US"        "2"     "0"
"4187"  "10"    "19"        "US"        "2"     "0"
"4188"  "10"    "19"        "US"        "2"     "0"

当我运行以下查询来更新总计时，为什么row id 1和row id 2显示为0？

UPDATE  likesd a
        INNER JOIN
        (
            SELECT  parent, country, SUM(votes) totalVotes
            FROM    likesd
            GROUP   BY parent
        ) b ON a.id = b.parent and a.country = b.country
SET     a.votes = b.totalVotes; select * from likesd;

当我这样做时：

SELECT  parent, country, SUM(votes) totalVotes
            FROM    likesd
            GROUP   BY parent;

我可以看到结果中的所有行，但前两行不会更新。

我的sql出错了吗？我该怎么做呢？另外，你在我使用的sql中看到任何问题吗？

Answer 1

您还应该在更新时检查国家/地区时将国家/地区也放在group by子句中。

UPDATE  likesd a
        INNER JOIN
        (
            SELECT  parent, country, SUM(votes) totalVotes
            FROM    likesd
            GROUP   BY parent, country
        ) b ON a.id = b.parent and a.country = b.country
SET     a.votes = b.totalVotes; select * from likesd;

修改如果出现意外结果，您可以尝试使用update语句 -

UPDATE Likesd a SET Voltes = (SELECT SUM(Votes) FROM Likesd b WHERE b.PARENT = a.Id AND b.Country = a.Country)

更新查询不会更新几行

1 个答案: