SELECT
:
SELECT
clause lists the column names that you want
displayed in answer to the query.
FROM
:
FROM
clause indicates the table of data "FROM"
which you want to retrieve information.
WHERE
:
WHERE
clause is used to screen the rows you want to
retrieve, based on some criteria, or search condition, that you
specify. This clause is optional, and, if omitted, all rows from the
table are retrieved.