Include an AS clause to assign a name to a select term or to a table name. You can use this name elsewhere in the statement to reference the select term. The name is often referred to as an alias.
When you use the AS clause on a non-aggregate column, you can reference the name in
WHERE,
ORDER BY,
GROUP BY, and
HAVING clauses. When you use the
AS clause on an aggregate column, you can reference the name only in an
ORDER BY clause.
The AS clause in the following statement instructs Pervasive PSQL to assign the name Total to the select term SUM (Amount_Paid) and order the results by the total for each student:
The keyword AS is optional when used for table aliases as in this next example. When you use the AS clause on a table name in a
FROM clause, you can reference the name in a
WHERE,
ORDER BY,
GROUP BY, and
HAVING clause.