Alias name should be preceded by “AS”

In my earlier post on Understanding Column alias I have shown different methods of using a column alias name

SELECT 100number
SELECT 100.number
SELECT 100'number'
SELECT 100"number"
SELECT 100[number]

As you see all works fine with number as the column alias name

But However you need to use AS before the alias name for better reading and standard
Now execute the following and see the result

drop table if exists #employee_master;
create table #employee_master
emp_id int, emp_name varchar(100), dob datetime
insert into #employee_master
select 1,'Sankar','19760910' union all
select 2,'Kamal','19680707' union all
select 3,'Rajesh','19661222'
Select emp_id, emp_name dob from #employee_master

The result is

emp_id      dob
----------- ------------
1           Sankar
2           Kamal
3           Rajesh

The SELECT statement lists out three columns but the output has only two columns. The data of emp_name are listed under the column name dob. It is because the missing comma between column names makes that dob becomes alias name for emp_name which is confusing and hard to detect if there are hundreds of lines in the procedure.

So in my opinion ,Alias name should be preceded by “AS” to avoid confusion and unexpected result.

What do you think of this?


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