How to execute complex subqueries in SQLite?

5 months ago

1 minute

To execute complex subqueries in SQLite, you can use either nested subqueries or use the WITH clause for recursive queries. Here are examples of both methods:

Utilizing nested subqueries:

SELECT column1, column2
FROM table1
WHERE column1 IN (SELECT column1 FROM table2 WHERE column2 = 'value');

In this example, the inner subquery is executed first and returns the results that meet the criteria, which are then further filtered and processed by the outer query.

Performing a recursive query using a WITH clause:

WITH recursive cte AS (
  SELECT column1, column2
  FROM table1
  WHERE column1 = 'value'
  UNION ALL
  SELECT column1, column2
  FROM table2
  WHERE column2 IN (SELECT column1 FROM cte)
)
SELECT *
FROM cte;

In this example, a recursive common table expression (CTE) is created using a WITH clause, where multiple SELECT statements are defined and connected together using UNION ALL. Finally, this CTE is referenced in the outer query to retrieve the final result.