17.05 - Example: Scalar Subquery in the Select List of a SELECT Statement - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Manipulation Language

Product
Advanced SQL Engine
Teradata Database
Release Number
17.05
Published
January 2021
Language
English (United States)
Last Update
2021-01-22
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You can specify a scalar subquery as a column expression or parameterized value in the select list of a query. You can assign an alias to a scalar subquery defined in the select list, thus enabling the rest of the query to reference the subquery by that alias.

The following example specifies a scalar subquery (SELECT AVG(price)…) in its select list with an alias (avgprice) and then refers to it in the WHERE clause predicate (t2.price < avgprice).

     SELECT category, title,(SELECT AVG(price)
                             FROM movie_titles AS t1
                             WHERE t1.category=t2.category) AS avgprice
     FROM movie_titles AS t2
     WHERE t2.price < avgprice;

For additional examples of specifying scalar subqueries in SELECT statements, see: