Question

I have a table like below (using SQL server 2008 R2 Enterprise):

create table Message
(
ID int Not Null Primary Key,
Text nvarchar(100) not null,
Code nvarchar(50) null
)

Insert Into Message Values (1,'Hello Everybody','T6/45')
Insert Into Message Values (2,'Hello Everybody',Null)
Insert Into Message Values (3,'Hello Everybody','T6/45')
Insert Into Message Values (4,'Hello Everybody','T6/45')
Insert Into Message Values (5,'Hello Everybody','T6/70')
Insert Into Message Values (6,'Hello Everybody','T6/70')
Insert Into Message Values (7,'Hello','T6/70')
Insert Into Message Values (8,'Hello','T6/45')
Insert Into Message Values (9,'Hello Everybody',Null)
Insert Into Message Values (10,'Hello Everybody','T6/70')
Insert Into Message Values (11,'Hello',Null)

I need to get all the records which are having same Text but different Code. And Code will not be Null .

So expected output will be:

Insert Into Message Values (1,'Hello Everybody','T6/45')
Insert Into Message Values (5,'Hello Everybody','T6/70')
Insert Into Message Values (7,'Hello','T6/70')
Insert Into Message Values (8,'Hello','T6/45')

I tried below query, but it is returning several rows:

select m1.* 
from Message M1 
With (nolock)
JOIN Message M2 
With (Nolock) 
On m1.Text=m2.Text
where (m1.ID<>m2.ID 
  and m1.Code<>m2.Code 
  and m1.Code is not null)

How can I get expected result?

Also, this is a sample DB. I need to run the query on a table having arount 50 Million records. So any optimized query will be of great help.

Answer 1

SELECT ID,TEXT,CODE
FROM message
WHERE ID IN 
(
  SELECT MIN(ID) FROM message
 WHERE CODE IS NOT NULL GROUP BY TEXT,CODE
)

or

SELECT 
   MIN(ID)
   ,TEXT
   ,CODE 
FROM message
WHERE CODE IS NOT NULL GROUP BY TEXT,CODE
ORDER BY MIN(ID)