Using an Alias column in the where clause in ms-sq

问题:

I know you cannot use a alias column in the where clause for T-SQL; however, has Microsoft provided some kind of workaround for this?

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回答1:

One workaround would be to use a derived table.

For example:

select *
from 
   (
   select a + b as aliased_column
   from table
   ) dt
where dt.aliased_column = something.

I hope this helps.

回答2:

Depending on what you are aliasing, you could turn it into a user defined function and reference that in both places. Otherwise your copying the aliased code in several places, which tends to become very ugly and means updating 3+ spots if you are also ordering on that column.