Common Table Expressions are a SQL coding technique supported by Oracle, Db2, SQL Server and others.
Common Table Expressions are also referred to as CTEs, the WITH clause or Subquery Query Factoring clauses.
Think subquery, SQL within a SQL statement when thinking of CTEs. A CTE can be a useful SQL coding
technique for code containing subqueries to make your code more readable and possibly to make your code
more efficient, two great benefits.