And if you want to have just the ones that are in that time frame, plus mark the missing ones, then add this at the end...
| where MyFlag="On Time"
| append [| makeresults
| eval mydata="client1,05:00:00,05:15:00!!!!client2,09:30:00,09:45:00!!!!client3,07:30:00,07:42:00!!!!client4,07:00:00,07:25:00!!!!client5,05:00:00,05:30:00!!!!client6,00:30:00,01:15:00"
| makemv delim="!!!!" mydata
| mvexpand mydata
| rex field=mydata "(?<MyClient>.+?),(?<LowTime>[^,]+),(?<HighTime>[^,]+)"
| table MyClient LowTime HighTime
]
| stats values(*) as * by MyClient
| eval MyFlag = coalesce(MyFlag, "Missing")
... View more