SQL for Min Max Dates

Start      End
10:01      10:12     (A)
10:03      10:06     (A)
10:05      10:25     (C)
10:14      10:42     (D)
10:32      10:36     (E)
开发者_如何学Python

When I query for A, I need

Start      End
10:12      10:03     (A)

what is the sql query pls. Thanks

Guys, Thanks for your replies. My objective is to calculate a time sheet. Employee will punch in and punch out. I store those records in one table. That table has time and a field for in punch or out punch. Employee may go out for lunch or other reasons and punches for out and in. I need deduct those times and get the working hours. My table will look like below :

    PunchTime  EmpCode    IsInpunch
    10:01 AM   (A)        T
    12:03 PM   (A)        F            (this isoutpunch) 
    01:05 PM   (A)        T
    07:14 PM   (A)        F
    10:32 AM   (B)        T

For (A)'s time 7.14 - 10.01 is the total hours, but he was not there between 12.03 to 01.05 so I need to deduct the lunch time and get the total hours. How to do this in Query

SELECT max(start), min(end) FROM table WHERE column='A';

If you looking for total time this will do it.

DECLARE @testData table (
Punchtime datetime, empcode char(3), isInPunch char(1))


INSERT INTO @testData
Values
('10:01 AM ',  '(A)', 'T'),
('12:03 PM',   '(A)', 'F'),
('01:05 PM',   '(A)', 'T'),
('07:14 PM',   '(A)', 'F'),
('10:32 AM',   '(B)', 'T')

;WITH CTE as(
SELECT 
    DENSE_RANK() over (Partition by empcode , isInPunch  Order by punchTime) id,
    Punchtime,
    empcode,
    isInPunch

FROM 
    @testData
WHERE 
         empcode = '(A)'
    )
SELECT
     Cast(cast(sum(
        cast(outTime.punchTime as float) - cast(inTime.punchTime as float)
        )as datetime) as time)
FROM 
     CTE inTime
     INNER JOIN CTE outTime
     ON inTime.empcode = outTime.empcode
         AND inTime.id = outTime.id
        AND inTime.isInPunch = 'T'
        and outTime.isInPunch = 'F'

This query finds the First PunchTime of a Punch='T' after a Punch='F' (non working times). Then you can simply calculate datediff and similar stuff.

SELECT  EmpCode,
        PunchTime StartTime,
        (SELECT TOP 1 PunchTime from Table1 
         where IsInpunch = 'T' and EmpCode=T.EmpCode and PunchTime>T.PunchTime
         order by PunchTime) EndTime
FROM    Table1 T
WHERE   IsInpunch = 'F'