Row_Number() with union query

Question

I have an sql query that returns rows from two tables with same column names. I need a row number of all records in a complete result set.

Following is the query

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Answer 1

A slightly better way would be :-

with resultset1 as(
   select Id, VersionNumber from documents where id=5 
   Union all  
   select Id, VersionNumber from versions where id=5
), resultset2 as(
   select Id, VersionNumber, ROW_NUMBER() OVER(ORDER BY Id) ROW_NUM
   from resultset1
)
select * from resultset2 WHERE VersionNumber = 5