根据计数条件指定的 MySQL 更新

Question

我有以下问题: 我想更新 COUNT 条件大于 1 的所有行，否则我想更新除 1 之外的所有行。它还应该根据 other_ID 进行更新。

虚拟表:

+----+----------+----------+-------------+
| id | other_ID | cirteria | updatefield |
+----+----------+----------+-------------+
|  1 |        1 |        1 |           0 |
|  2 |        1 |        1 |           0 |
|  3 |        1 |     1234 |           0 |
|  4 |        2 |        2 |           0 |
|  5 |        2 |        1 |           0 |
|  6 |        2 |        1 |           0 |
|  7 |        4 |       20 |           0 |
|  8 |        4 |        1 |           0 |
|  9 |        4 |       60 |           0 |
| 10 |        5 |        1 |           0 |
| 11 |        5 |        1 |           0 |
| 12 |        6 |        5 |           0 |
+----+----------+----------+-------------+

预期结果:

+----+----------+----------+-------------+
| id | other_ID | cirteria | updatefield |
+----+----------+----------+-------------+
|  1 |        1 |        1 |           1 |
|  2 |        1 |        1 |           1 |
|  3 |        1 |     1234 |           0 |
|  4 |        2 |        2 |           0 |
|  5 |        2 |        1 |           1 |
|  6 |        2 |        1 |           1 |
|  7 |        4 |       20 |           0 |
|  8 |        4 |        1 |           1 |
|  9 |        4 |       60 |           0 |
| 10 |        5 |        1 |           0 |
| 11 |        5 |        1 |           1 |
| 12 |        6 |        5 |           0 |
+----+----------+----------+-------------+

我的想法:

UPDATE pics AS tu SET updatefield=1 WHERE criteria=1 AND (select count(*) as cnt2 from pics where criteria>1 group by other_id)>1;

错误:表“tu”被指定两次，既作为“UPDATE”的目标又作为单独的数据源

此外，我在获得正确的计数方面也遇到了问题: SELECT other_id, count() as cnt FROM pics AS ts WHERE criteria=1 and (select count() as cnt2 from pics where criteria>1)>0 GROUP BY other_id;

我想为 other_id=5 获取 cnt = 1，但我得到 cnt=2

与 选择 other_id, COUNT(*) AS cnt2 来自图片 其中条件>1 按 other_id 分组；

我得到了我想要更新更新字段的所有 other_ids 。但如何将其与更新连接起来呢？以及如何获取 other_id=5 之外的所有内容

Answer 1

您可以将子查询别名为另一个查询，例如:

UPDATE test
SET updatefield = 1
WHERE updatefield = 0 AND criteria = 1
AND other_id IN (
    SELECT a.id FROM (
        SELECT other_id AS id
        FROM test
        WHERE criteria > 1
        GROUP BY other_id
        HAVING COUNT(*) > 1
     ) a
  );

这是SQL Fiddle 。

更新

这将更新符合条件 0 和 >1 的记录的 ID。现在，要更新具有 1 条件的多个记录的记录，您需要执行如下操作:

UPDATE test
SET updatefield = 1
WHERE updatefield = 0 AND criteria = 1
AND id IN (
    SELECT a.id FROM (
        SELECT MIN(id) AS id
        FROM test
        WHERE criteria = 1
        GROUP BY other_id
        HAVING COUNT(*) > 1
     ) a
  );