For example, I have the following table:
UserId Department1 Department2 ------------------------------ 1 Sales Marketing 2 Research 3 Sales And I want to get the following Results
DistinctDepartments ------------------- Sales Marketing Research I found lots of solutions that show me the distinct combined values of multiple columns, but I need the overall distinct values, as if all values would be in the same column.
Thankyou
Chris
Using union is definitely a reasonable approach to this problem. In most databases, though, the following may be faster:
select distinct (case when n = 1 then Department1 else Department2 end) from tab cross join (select 1 as n union all select 2) n The reason is that the table is only scanned once, rather than once for each column. This can be particularly important when tab is not really a table, but a more expensive view. (And some databases support unpivot which behaves similarly to this.)
Try to use union with both columns
select Department1 from tab union select Department2 from tab NOTE: union command eliminates duplicates
