WITH Clauses in SELECT

WITH clauses are concomitant queries within a larger, primary query. Vertica can evaluate WITH clauses in two ways: 

• Inline expansion (default): Vertica evaluates each WITH clause every time it is referenced by the primary query.
• Materialization: Vertica evaluates each WITH clause once, stores results in a temporary table, and references this table as often as the query requires.

For details on WITH clause syntax and requirements, see WITH Clause in the SQL Reference Manual.