MySQL獲取具有值的第一個現有行或獲取另一個有序

Question

我需要為表編寫mysql查詢，如下所示：

id | product_id | version | status 
 1 | 1          | 1       | 0
 2 | 1          | 2       | 1
 3 | 1          | 3       | 0
 4 | 2          | 9       | 0
 5 | 2          | 10      | 0

我需要獲取行（product_id是唯一的-每個product_id一個），但是：
-如果有product_id的狀態為1的行-抓住它
-它沒有描述的行獲取具有較高值或版本的行

所以對於描述的表結果應該是

id | product_id | version | status 
 2 | 1          | 2       | 1
 5 | 2          | 10      | 0

我唯一的想法是獲取狀態為1的行，然后使用WHERE product_id NOT IN進行第二次查詢，然后按版本DESC和GROUP BY product_id進行排序

Answer 1

在這種情況下可以重新加入表格

SELECT p1.id, p1.product_id, p1.version, p1.status FROM products p1
  LEFT OUTER JOIN (
    SELECT MAX(version) AS version FROM products p2
   ) p2 ON p1.version = p2.version OR p1.status = 1
GROUP BY p1.product_id

SQL小提琴

Answer 2

您可以使用UNION來實現

select myTable.id, product_id, version, status from myTable
where id in(select id from myTable where status > 0) 
union
select myTable.id, product_id, version, status from myTable
join (select max(id) as id from myTable group by product_id) 
as m on m.id = myTable.id 
and product_id  not in(select product_id from myTable where status > 0 )