MySQL查询，MAX() + GROUP BY + WHERE

Question

如何获取包含每个分组集的最大值的行？我有这个mysql

SELECT ticketId, version, storeId, `status` FROM ticket where storeId = 1 AND status = 0;

并得到结果。

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我想要找到不同ticketId中的最大版本，行应该是

ticket | version | storeId | status
---
  1    | 5       | 1       | 0  
  2    | 5       | 1       | 0

mysql会是怎样的？

Answer 1

使用聚合函数max

select ticketId,
    max(version),
    storeId,
    `status`
from ticket t
where storeId = 1
    and status = 0
group by ticketId,
    storeId,
    `status`

如果禁用了ONLY_FULL_GROUP_BY，您可以使用：

select ticketId,
    max(version),
    storeId,
    `status`
from ticket t
where storeId = 1
    and status = 0
group by ticketId;

Answer 2

只需使用group by和max即可

SELECT ticketId as ticket, MAX(version) AS version, storeId, `status`
FROM ticket 
WHERE storeId = 1
AND status = 0
GROUP BY ticketId