SQL statement for retrieving the first record of each group of data

-- Operation Log table
Create   Table Joblog -- Operation Log table
(
Joblogid] Int   Not   Null , -- Primary Key
Functionid Nvarchar ( 20 ) Null , -- Function ID
Operatetime Datetime   Null -- Operation Time
) On   Primary
Go
Alter   Table Joblog Add  
Constraint Pk_joblog Primary   Key   Clustered (Joblogid) On   Primary
Go

-- All records in the operation log table
Select   *   From Joblog
Query results:
1 001 2007 - 11 - 01
2 001 2007 - 11 - 02
3 001 2007 - 11 - 03
4 002 2007 - 11 - 04
5 002 2007 - 11 - 05
6 003 2007 - 11 - 06
7 004 2007 - 11 - 07
8 004 2007 - 11 - 08
9 005 2007 - 11 - 09
10 005 2007 - 11 - 10

-- Last operation record of each function
Select   *   From Joblog
  Where Joblogid In
( Select   Top   1 Joblogid From Joblog
Where A. functionid = Functionid Order   By Operatetime Desc
)
Query results:
3 001 2007 - 11 - 03
5 002 2007 - 11 - 05
6 003 2007 - 11 - 06
8 004 2007 - 11 - 08
10 005 2007 - 11 - 10