If you use an ‘Order By’ clause, in ASE you can freely mix column names and column aliases which you can prefix with a table name or a table alias.

In MS SQL Server, a column alias cannot be prefixed with a table name or table alias.

Example

create table Tab (Col varchar(30))

select Col from Tab as T order by Col

select Col from Tab as T order by T.Col

select Col as C from Tab as T order by T.Col

select Col as C from Tab as T order by C

select Col as C from Tab as T order by Col

go

-- This statement will not work on MS SQL Server

select Col as C from Tab as T order by T.C

go

drop table Tab

Note: If you choose a unique column alias, there is no need to prefix it.