HowcanIwritequerywherequerywithspecificwherecondition?

1  

You have tagged multiple databases, assuming it to be a SQL Server.

您已标记多个数据库,假设它是SQL Server。

Try this query, it will give you the desired output.

试试这个查询,它会给你想要的输出。

SELECT Id,RegistrationId ,GroupId,ItemId,Value FROM
(
  SELECT * ,
  ROW_NUMBER() OVER( PARTITION BY GroupId,ItemId   ORDER BY RegistrationId DESC) RN
  FROM [TABLE_NAME]
 ) T
WHERE T.RN=1
ORDER BY RegistrationId DESC

Example with sample data

示例数据示例

;WITH MY AS 
(
  SELECT * FROM (VALUES
  (2345 ,  68038  ,  677 , 672 , 679 ),
  (3562 ,  68038  ,  357 , 783 , 423 ), 
  (8236 ,  NULL   ,  268 , 578 , 914 ),
  (7327 ,  NULL   ,  677 , 672 , 467 ),
  (8733 ,  NULL   ,  357 , 783 , 234 ) 
  ) T(Id,RegistrationId ,GroupId,ItemId,Value)
)

SELECT Id,RegistrationId ,GroupId,ItemId,Value FROM
(
  SELECT * ,    
  ROW_NUMBER() OVER( PARTITION BY GroupId,ItemId   ORDER BY RegistrationId DESC) RN
  FROM MY
 ) T
WHERE T.RN=1
ORDER BY RegistrationId DESC

Output:

+------+----------------+---------+--------+-------+
| Id   | RegistrationId | GroupId | ItemId | Value |
+------+----------------+---------+--------+-------+
| 3562 | 68038          | 357     | 783    | 423   |
+------+----------------+---------+--------+-------+
| 2345 | 68038          | 677     | 672    | 679   |
+------+----------------+---------+--------+-------+
| 8236 | NULL           | 268     | 578    | 914   |
+------+----------------+---------+--------+-------+

0  

I tried something like that and it worked, but its bit a hardcoded way:

我尝试了类似的东西并且它有效,但它有点硬编码方式:

    SELECT *
    FROM   MY
    WHERE  RegistrationId IS NOT NULL
    AND    GroupId IN (677, 357)
    UNION ALL
    SELECT *
    FROM   xxtest_tolga
    WHERE  GroupId NOT IN (677, 357);

Hope it works for you.

希望对你有效。