SQL Common Table Expressions Practice Questions

A CTE (common table expression) is a named result defined with WITH that the rest of the query can use like a table.

• It exists only for that one statement.
• It turns nested subqueries into steps you read top to bottom.
• You can chain several, each building on the one before (shown here).

Use WITH RECURSIVE when rows point to other rows in the same table, like managers and their reports.

• Typical cases: org charts, category trees, bills of materials, date series.
• It has an anchor query (the start) and a recursive part that joins back until nothing new appears.
• Always add a stop condition or depth limit so a cycle in the data cannot loop forever.