You can set table aliases in SQL typing the identifier right after the table name.
SELECT * FROM table t1;
You can even use the keyword AS to indicate the alias.
SELECT * FROM table AS t1;
What's the difference between them if any?
I see old DBA people tend to write statements without AS, but most of the new tutorials use it.
Update: I know what's the purpose of table and column aliases. I'm curious, what's the reason for having a separate keyword for setting aliases while it works without it as well.