thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Data & Analytics · Foundational

Column Alias

A temporary name given to a column or expression in a query's result using AS.

Definition

Aliases improve readability and name calculated columns. They exist only for the query's duration and, given the logical processing order, are visible in ORDER BY but not in WHERE or GROUP BY in standard SQL. Some engines, Snowflake among them, relax this rule.

Example

SELECT Quantity * UnitPrice AS LineTotal FROM OrderLines;

Exam tip

Standard SQL does not let WHERE reference a SELECT alias; repeat the expression or use a CTE.

Related terms