Mysql如何使用count函数更新n行？

在下表中，如果同一组织的总记录超过500条，我想将delete设置为true 我想根据createdate来做，这样如果记录超过500条，旧记录就会被删除，并使该orgid的记录总数达到500条

这是我的桌子

Table A
+----+-------+------------------+--------+------------+
| id | orgid | transactionvalue | delete | createdate |  
+----+-------+------------------+--------+------------+
|  1 |     1 |              123 | false  | 05-16-2020 |  
|  2 |     1 |              412 | false  | 07-16-2020 |  
|  3 |     2 |              762 | false  | 07-16-2020 |  
+----+-------+------------------+--------+------------+

这是我正在尝试的问题

update A 
set 
  delete = true 
where orgid = 1 
and (select count(*) as records 
      from (select * 
            from A order by createdate
    ) as pseudotable)) >500

---

使用子查询和联接更新

   UPDATE tablea
            INNER JOIN
        (select orgid, count(*) cnt from tablea group by orgid
        ) b ON tablea.orgid = b.orgid 
    SET 
        delete = 'true'
    where cnt>500

---

使用子查询和联接更新

   UPDATE tablea
            INNER JOIN
        (select orgid, count(*) cnt from tablea group by orgid
        ) b ON tablea.orgid = b.orgid 
    SET 
        delete = 'true'
    where cnt>500

您可以使用row_number查找每个组织的第500条记录，然后使用该信息：

update tablea a join
       (select a2.org_id, a2.created_date as cutoff_created_date
        from (select a2.*,
                     row_number() over (partition by a2.org_id order by create_date desc) as seqnum
              from tablea a2
             ) a2
        where a2.seqnum = 500
       ) a2
       on a.org_id = a2.org_id and and
          a.created_date < a2.cutoff_created_date
    set delete = true;

您可以使用row_number查找每个组织的第500条记录，然后使用该信息：

update tablea a join
       (select a2.org_id, a2.created_date as cutoff_created_date
        from (select a2.*,
                     row_number() over (partition by a2.org_id order by create_date desc) as seqnum
              from tablea a2
             ) a2
        where a2.seqnum = 500
       ) a2
       on a.org_id = a2.org_id and and
          a.created_date < a2.cutoff_created_date
    set delete = true;

---

我没有尝试所有其他答案，它们可能是正确的，但这对我来说是有效的

update A 
set `delete` = true 
where orgid = 1 AND id IN (
SELECT id FROM  A where orgid = 1
order by createdate DESC
LIMIT 500,18446744073709551615);

---

我没有尝试所有其他答案，它们可能是正确的，但这对我来说是有效的

update A 
set `delete` = true 
where orgid = 1 AND id IN (
SELECT id FROM  A where orgid = 1
order by createdate DESC
LIMIT 500,18446744073709551615);

---

您可以通过为3家公司提供样本数据来澄清和简化5家公司各保留2.您正在运行的MySQL版本是什么？@EricBrandt 8.0.17您可以通过为3家公司提供样本数据来澄清和简化5家公司各保留2.您正在运行的MySQL版本是什么？@EricBrandt 8.0.17Createdate必须在这里的某个地方提供功能？订购createdate描述？createdate必须在这里的某个地方出现？按createdate描述订购？