How to use one data field into another case expression in the same query

I want to use SNumber in the second part of CASE expression but not sure how to use it?

 (case when(PE.EDateTime is not NULL and cast(PE.EDateTime as time) < '12:30') then cast(format(PE.EDateTime,'yyyyMMddhhmm') as varchar(50))+'AM'           when (PE.ADate is not NULL and cast(PE.ADate as time) < '12:30') then cast(format(PE.ADate,'yyyyMMddhhmm') as varchar(50))+'AM'           when (PE.EDateTime is not NULL and cast(PE.EDateTime as time) >= '12:30') THEN  cast(format(PE.EDateTime,'yyyyMMddhhmm') as varchar(50))+'PM'           when  (PE.ADate is not NULL and cast(PE.ADate as time) > '12:30') then cast(format(PE.ADate,'yyyyMMddhhmm') as varchar(50))+'PM'           else null           end) as SNumber  

I want to use SNumber here below in the same query but I am not able to use this as this all belongs to one query. Is there any way to use the above in below CASE? I want to use something like below.

        case when (SNumber contains 'AM') then 'AM'          when SNumber contains 'PM') then 'PM'          else null           end as Session,  

https://stackoverflow.com/questions/67363054/how-to-use-one-data-field-into-another-case-expression-in-the-same-query May 03, 2021 at 11:05AM