select rows with events related with another events in the same query column - sql

Question

I need to select rows with EventTypeID = 19 which does not have related EventtypeID = 21 LoggedOn exactly 4 minutes earlier for the same EmployeeID. Here's the query bellow and some raw output:
SELECT * FROM
(
SELECT rcp..EventLogEntries.EmployeeID, rcp..EventLogEntries.EventTypeID, rcp..EventLogEntries.TerminalID, rcp..EventLogEntries.LoggedOn
FROM rcp..EventLogEntries
WHERE rcp..EventLogEntries.terminalid = 3
UNION
SELECT viso..AccessUserPersons.UserExternalIdentifier, rcp..EventTypes.ID, rcp..Terminals.ID, viso..EventLogEntries.LoggedOn
FROM viso..EventLogEntries, viso..AccessUserPersons, rcp..Terminals, rcp..EventTypes
WHERE viso..EventLogEntries.LocationID = 10
AND viso..EventLogEntries.EventCode = 615
AND rcp..EventTypes.Code = 36
AND viso..EventLogEntries.PersonID = viso..AccessUserPersons.ID
AND viso..EventLogEntries.locationID = rcp..Terminals.TerminalTAID
) results
ORDER BY LoggedOn
EmployeeID EventTypeID TerminalID LoggedOn
273 19 3 2018-12-04 12:31:23.000
273 21 3 2018-12-04 12:34:18.000
483 19 3 2018-12-04 12:40:10.000
268 19 3 2018-12-04 13:19:23.000
273 21 3 2018-12-04 13:28:00.000
273 19 3 2018-12-04 13:32:00.000
459 19 3 2018-12-04 15:01:04.000
What I need to achieve is:
EmployeeID EventTypeID TerminalID LoggedOn
273 19 3 2018-12-04 12:31:23.000
483 19 3 2018-12-04 12:30:10.000
268 19 3 2018-12-04 13:19:23.000
459 19 3 2018-12-04 15:01:04.000
TerminalID column value is always 3 in that scenario and it's not related with any query condition, but must be in the output for syntax requirement in the futher processing.

Answer 1

The bad practice to join tables using conditions in WHERE. The block WHERE need to use to filter first of all.
And aliases help to make code shorter.
SELECT * FROM
(
SELECT EmployeeID, EventTypeID, TerminalID, LoggedOn
FROM rcp..EventLogEntries
WHERE terminalid = 3
UNION
SELECT p.UserExternalIdentifier, et.ID, t.ID, el.LoggedOn
FROM viso..EventLogEntries el
JOIN viso..AccessUserPersons p ON el.PersonID = p.ID
JOIN rcp..Terminals t ON el.locationID = t.TerminalTAID
JOIN rcp..EventTypes et ON --!!! no any condition here
WHERE el.LocationID = 10
AND el.EventCode = 615
AND et.Code = 36
) results
ORDER BY LoggedOn
Try to use the following:
WITH cteData AS
(
SELECT EmployeeID, EventTypeID, TerminalID, LoggedOn
FROM rcp..EventLogEntries
WHERE terminalid = 3
UNION
SELECT p.UserExternalIdentifier, et.ID, t.ID, el.LoggedOn
FROM viso..EventLogEntries el
JOIN viso..AccessUserPersons p ON el.PersonID = p.ID
JOIN rcp..Terminals t ON el.locationID = t.TerminalTAID
JOIN rcp..EventTypes et ON --!!! no any condition here
WHERE el.LocationID = 10
AND el.EventCode = 615
AND et.Code = 36
)
SELECT q19.*
FROM
(
SELECT *
FROM cteData
WHERE EventTypeID=19
) q19
LEFT JOIN
(
SELECT *
FROM cteData
WHERE EventTypeID=21
) q21
ON q19.EmployeeID=q21.EmployeeID
WHERE (DATEDIFF(MINUTE,q19.LoggedOn,q21.LoggedOn)>4 OR q21.LoggedOn IS NULL)
If there don't need any conditions you can use CROSS JOIN.
I got your result using your data:
WITH cteData AS(
SELECT *
FROM (VALUES
(273,19,3,CAST('2018-12-04 12:31:23.000' AS datetime)),
(273,21,3,CAST('2018-12-04 12:34:18.000' AS datetime)),
(483,19,3,CAST('2018-12-04 12:40:10.000' AS datetime)),
(268,19,3,CAST('2018-12-04 13:19:23.000' AS datetime)),
(273,21,3,CAST('2018-12-04 13:28:00.000' AS datetime)),
(273,19,3,CAST('2018-12-04 13:32:00.000' AS datetime)),
(459,19,3,CAST('2018-12-04 15:01:04.000' AS datetime))
)v(EmployeeID,EventTypeID,TerminalID,LoggedOn)
)
SELECT q19.*
FROM
(
SELECT *
FROM cteData
WHERE EventTypeID=19
) q19
LEFT JOIN
(
SELECT *
FROM cteData
WHERE EventTypeID=21
) q21
ON q19.EmployeeID=q21.EmployeeID
WHERE (DATEDIFF(MINUTE,q19.LoggedOn,q21.LoggedOn)>4 OR q21.LoggedOn IS NULL)

Answer 2

Small change done in this part:
ON q19.EmployeeID=q21.EmployeeID AND q19.LoggedOn=dateadd(mi, 4, q21.LoggedOn)
WHERE q21.LoggedOn IS NULL