SQL Server conditional query - sql-server

Question

I have a table for attendance entries looking like this :
I need a query to export the following format :
which present the Check-in and Check-out timings using British/French format (103)
I tried the following query :
SELECT
UserID,
(SELECT MIN(checktime)
FROM [FingerPrint].[dbo].[CHECKINOUT] I
WHERE CONVERT(VARCHAR(10), i.checktime, 111) = CONVERT(VARCHAR(10), p.checktime, 111)
AND i.userid = p.userid),
(SELECT MAX(checktime)
FROM [FingerPrint].[dbo].[CHECKINOUT] I
WHERE CONVERT(VARCHAR(10), i.checktime, 111) = CONVERT(VARCHAR(10), p.checktime, 111)
AND i.userid = p.userid)
FROM
[FingerPrint].[dbo].[CHECKINOUT] p
GROUP BY
p.checktime, p.UserID
Basically I need a query to select the minimum time (check-in) and maximum time (check-out) for each day using the export format above, yet when there is no value for check-in and check-out, then query should return (null) for time.

Answer 1

So basically you start with something like this:
SELECT UserId,
CAST(CheckTime As Date) As CheckDate,
MIN(CheckTime) As CheckIn,
MAX(CheckTime) As CheckOut
FROM [FingerPrint].[dbo].[CHECKINOUT]
GROUP BY UserId, CAST(CheckTime As Date)
For older versions of sql server (2005, 2000), you can use convert to char(10) to isolate the date part of the datetime column:
SELECT UserId,
CONVERT(char(10), CheckTime, 102) As CheckDate, /*Convert datetime format to Date*/
MIN(CheckTime) As CheckIn,
MAX(CheckTime) As CheckOut
FROM [FingerPrint].[dbo].[CHECKINOUT]
GROUP BY UserId, CONVERT(char(10), CheckTime, 102)
see fiddle here
Then you need to figure out what you want to display if the user have only one record for a day.
Also, what happens on night shifts, when a user checks in on one date, and checks out on the other date?
A better solution would be to add a bit column to specify if the record is for check in or for check out.
Update
Using case you can check if the current time is before or after whatever time of day you want to set up as the delimiter between check in and check out. In this example I've used 12 pm.
SELECT UserId,
CONVERT(char(10), CheckTime, 102) As CheckDate, /*Convert datetime format to Date*/
CASE WHEN MIN(CheckTime) <> MAX(CheckTime) THEN
MIN(CheckTime)
ELSE
CASE WHEN MIN(CheckTime) < DATEADD(Hour, 12, CONVERT(Datetime, CONVERT(char(10), CheckTime, 102), 102)) THEN
NULL
ELSE
MIN(CheckTime)
END
END As CheckIn,
CASE WHEN MIN(CheckTime) <> MAX(CheckTime) THEN
MAX(CheckTime)
ELSE
CASE WHEN MAX(CheckTime) > DATEADD(Hour, 12, CONVERT(Datetime, CONVERT(char(10), CheckTime, 102), 102)) THEN
NULL
ELSE
MAX(CheckTime)
END
END As CheckOut
FROM [CHECKINOUT]
GROUP BY UserId, CONVERT(char(10), CheckTime, 102)
Here is the relevant fiddle.