What is the point using "AS" keyword in SQL when aliasing can be done without it?

Question

1. Select salary*12 as "Annual Salary" from Employee;
2. Select salary*12 "Annual Salary" from Employee;

Both queries will give the same result, would "AS" make some difference? if yes, what it is? if no, then what is point using it?

Answer 1

I think the reason is simple. Consider code such as the following:

select a, b, c, d
. . .

It is very easy to occasionally skip the comma:

select a b, c, d

If you don't use as then this looks like correct code and it can be difficult to figure out. If you always use as for column aliases, then you know it is incorrect.