In SQL, what is the letter after a table name in a select statement?

Question

In

SELECT a.NAME, a.NUMBER, a.STRING, a.RDB$DB_KEY FROM ADMIN a

what does a stand for?

Thanks.

Answer 1

A is an alias for the table.

You can change a to any valid identifier, it isn't dependant on the underlying schema. Usually it's used to differentiate fields from different tables, saves you typeing the full table name each time (makes the SQL easier to read with a short alias).

It isn't actually required in the sample you gave,

SELECT NAME, NUMBER, STRING, RDB$DB_KEY FROM AMDIN

should work just as well