Question

SQL小提琴here

"id"    "type"  "parent"    "country"   "totals"
1       3       0           US          0       //Desired output 5
2       10      1           US          0
3       10      1           US          0
4       10      1           US          0
5       10      1           US          0
6       10      1           US          0

7       3       0           US          0       //Desired output 5
8       10      7           US          0
9       10      7           US          0
10      10      7           US          0
11      10      7           US          0
12      10      7           US          0

13      3       0           SE          0       //Desired output 1
14      10      13          SE          0

15      3       0           SE          0       //Desired output 3
16      10      15          SE          0
17      10      15          SE          0
18      10      15          SE          0

在上表中，我正在尝试更新所有父母的子女数(how many children each has)。

父母是type 3，孩子是type 10，而且这个国家就在旁边。

我要做的是：

`select count(*) as totalChildren ,parent,country where type= 10` then
`update table set totals = totalChildren where parent = parent from above and country = country from above`.

我在这些方面做了一些事情，但我似乎无处可去。你能帮我吗？

UPDATE  likesd a
        INNER JOIN
        (
            SELECT  country, parent, count(id) totalChildren
            FROM    likesd
            WHERE   type = 10
            GROUP   BY parent
        ) b ON a.country = b.country and a.parent=b.parent
SET     a.totals = b.totalChildren
WHERE   a.type = 3 and a.country = b.country;

编辑 - 工作答案

UPDATE  likesd a
        INNER JOIN
        (
            SELECT  country, parent, count(id) totalChildren
            FROM    likesd
            WHERE   type = 10
            GROUP   BY parent
        ) b ON a.id=b.parent and a.country = b.country
SET     a.totals = b.totalChildren
WHERE   a.type = 3 and a.id = b.parent and a.country = b.country;

Answer 1

这应该有效。您的a.parent = b.parent位于a.id = b.parent。

UPDATE  likesd a
    INNER JOIN
    (SELECT  parent, count(id) totalChildren
       FROM    likesd
      WHERE   type = 10
      GROUP   BY parent) b ON a.id=b.parent
SET     a.totals = b.totalChildren
WHERE   a.type = 3

（抱歉奇怪的格式化。）

SQL小提琴：http://sqlfiddle.com/#!2/0c5b0d/1

更新父母与父母明智和国家明智的总数的count（）

1 个答案: