仅当使用ROW_NUMBER对内部选择进行过滤时，才返回SQL数据

Question

I'm trying to get to the bottom of a query where there is only data returned if I filter on the inner select of the following statement:

Works:

SELECT * FROM 
(
SELECT    
      [szPhoneNo] Email      
      ,ROW_NUMBER() OVER (PARTITION BY CLID ORDER BY t_clientphone.PhoneType_Id ASC) AS Seq       
  FROM [SLacsis_SLM].[dbo].[T_ClientPhone] t_clientphone INNER JOIN 
  [SLacsis_SLM].[dbo].[TL_PhoneType] PT ON t_clientphone.PhoneType_ID = PT.PhoneType_ID  
  WHERE t_clientphone.szPhoneNo LIKE '%reg28%'          
            ) T where T.Seq = 1 --AND Email LIKE '%reg28%'

(10 rows returned)

Doesn't Work:

SELECT * FROM 
(
SELECT    
      [szPhoneNo] Email      
      ,ROW_NUMBER() OVER (PARTITION BY CLID ORDER BY t_clientphone.PhoneType_Id ASC) AS Seq       
  FROM [SLacsis_SLM].[dbo].[T_ClientPhone] t_clientphone INNER JOIN 
  [SLacsis_SLM].[dbo].[TL_PhoneType] PT ON t_clientphone.PhoneType_ID = PT.PhoneType_ID  
  --WHERE t_clientphone.szPhoneNo LIKE '%reg28%'            
            ) T where T.Seq = 1 AND Email LIKE '%reg28%'

(0 rows returned)

Can anyone explain why there are no rows returned for the second query and if there is a way that I can get around it?

I know that ROW_NUMBER is non-determistic when the PARTITION BY and ORDER BY columns aren't unique (which is the case for a few of the rows in the inner select).

I'll see if I can recreate the issue using a temp table in the mean time.

Answer 1

第二个查询中的第一个项目（即Seq = 1的项目）没有类似％REG28％的电子邮件。