A linked subquery is one that makes reference to a table column that is not listed in the FROM clause. The column may appear in the WHERE or in the PROJECTION clause. Correlated subqueries generally lead to decreased performance.

A correlated subquery is a subquery that refers to a column of a table that is not in its FROM clause. The column can be in the Projection clause or in the WHERE clause. In general, correlated subqueries diminish performance.

A correlated subquery is one that refers to a table column that is not in the FROM clause. The column can appear in either the Projection clause or the WHERE clause. Correlated subqueries, in general, degrade performance.