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Complex lag windows function help needed

Im racking my brain about how to do this and I dont think its possible but not sure what to even search for. So the below is a subset of the data (using example numbers) I am trying to use the lag function to populate the flag column. ``` Status Flag Connected -> Exiting Maillink Exiting -> Not equal to Connected OnCorp ( All rows stay OnCorp until we see Connected) Connected -> Reconnecting Mailink (It should stay Mailink for all rows until we see "Exiting" status ) ``` Is it possible in Sql? Using lag function in case statement to compare previous state is causing error [Sample Data][1] [1]: Sql Code (But erroring out ) -: ``` WITH base as ( select o.computername, o.currentuser, o.datetime, message, CASE WHEN LEN(split_part(substring(split_part(message, 'STATE', 2), 13), ',', 1)) <> 0 THEN split_part(substring(split_part(message, 'STATE', 2), 13), ',', 1) WHEN (message like 'WARNING%' OR message like 'OpenVPN%') THEN 'Start' WHEN message = 'SIGTERM[hard,] received, process exiting' THEN 'Exit1' WHEN message = 'Closing TUN/TAP interface' THEN 'Exit2' ELSE 'NO Status' END State1, CASE WHEN State1 = 'Start' THEN 1 WHEN State1 = 'RESOLVE' THEN 2 WHEN State1 = 'WAIT' THEN 3 WHEN State1 = 'AUTH' THEN 4 WHEN State1 = 'GET_CONFIG' THEN 5 WHEN State1 = 'ASSIGN_IP' THEN 6 WHEN State1 = 'ADD_ROUTES' THEN 7 WHEN State1 = 'CONNECTED' THEN 8 WHEN State1 = 'EXITING' THEN 9 END orderofoperation --row_number() over (partition by o.computername,o.currentuser,DATE(o.datetime) order by o.computername,o.currentuser,o.datetime) as rownumber from maillink_openvpn_logs_ext_schema.open_vpn_filtered o where o.message != 'message' and currentuser = 'wuellie' --and State1 in ('EXITING' ,'OpenVPN','RESOLVE','WAIT','AUTH','ASSIGN_IP','GET_CONFIG','ADD_ROUTES') order by o.datetime,orderofoperation ) select final.*, case when final.previous_record_state is null then ‘oncorp’ when final.currentstate = ‘CONNECTED’ then ‘maillink’ when final.previous_record_state is not null and final.previous_record_state not in (‘CONNECTED’) then lag(flag) partition by computername,currentuser, nextstateddatetime ::DATE order by nextstateddatetime when previous_record_state in (‘EXITING’) and lag(flag) partition by computername,currentuser, nextstateddatetime ::DATE order by nextstateddatetime = ‘maillink’ then ‘oncorp’ else lag(flag) partition by computername,currentuser, nextstateddatetime ::DATE order by nextstateddatetime end as flag from ( select b.computername,b.currentuser,b.State1 currentstate,b.datetime, lag(State1) over (partition by b.computername,b.currentuser,(b.datetime) ::DATE order by b.computername,b.currentuser, (b.datetime) ::TIMESTAMP,orderofoperation) as previous_record_state --lag(datetime) over (partition by b.computername,b.currentuser,b.datetime ::DATE order by b.computername,b.currentuser, (b.datetime) ::TIMESTAMP,orderofoperation) as nextdatetime from base b order by b.datetime,orderofoperation )final ``` ``` Computername username State datetime onCorp/mailink xyx ads start 2022-07-06T06:45:51 ONCORP xyx ads RESOLVE 2022-07-06T07:06:45 ONCORP xyx ads WAIT 2022-07-06T07:06:45 ONCORP xyx ads AUTH 2022-07-06T07:07:00 ONCORP xyx ads GET_CONFIG 2022-07-06T07:07:00 ONCORP xyx ads ADD_ROUTES 2022-07-06T07:07:01 ONCORP xyx ads CONNECTED 2022-07-06T07:07:01 MAILINK xyx ads EXITING 2022-07-06T07:07:01 MAILINK xyx ads RESOLVE 2022-07-06T07:07:46 ONCORP xyx ads WAIT 2022-07-06T07:07:46 ONCORP xyx ads AUTH 2022-07-06T07:07:50 ONCORP xyx ads GET_CONFIG 2022-07-06T07:07:51 ONCORP xyx ads ADD_ROUTES 2022-07-06T07:07:51 ONCORP xyx ads CONNECTED 2022-07-06T07:07:52 MAILINK xyx ads RECONNECTED 2022-07-06T07:08:01 MAILINK xyx ads WAIT 2022-07-06T07:08:02 MAILINK xyx ads AUTH 2022-07-06T07:08:09 MAILINK xyx ads RECONNECTED 2022-07-06T07:08:10 MAILINK xyx ads CONNECTED 2022-07-06T07:08:15 MAILINK xyx ads RECONNECTED 2022-07-06T07:08:20 MAILINK xyx ads CONNECTED 2022-07-06T07:09:01 MAILINK xyx ads EXITING 2022-07-06T07:10:50 MAILINK xyx ads START 2022-07-06T07:11:50 ONCORP ```
asked 2 months ago