postgresqlHow do I use the WITH statement in PostgreSQL?

The WITH statement in PostgreSQL is a convenient way to write complex queries. It allows you to define a set of subqueries which can then be used in the main query. This makes it easier to read and debug complex queries.

Here is an example of a WITH statement:

WITH subquery1 AS (
    SELECT *
    FROM table1
),
subquery2 AS (
    SELECT *
    FROM table2
)
SELECT *
FROM subquery1
JOIN subquery2
ON subquery1.id = subquery2.id;

This query consists of two subqueries, subquery1 and subquery2, which are defined in the WITH clause. These subqueries are then used in the main SELECT statement.

Code explanation

1. WITH clause: This is where the subqueries are defined.
2. Subqueries: These are the queries that are defined in the WITH clause.
3. SELECT statement: This is the main query that uses the subqueries defined in the WITH clause.

Helpful links

• PostgreSQL Documentation on WITH
• W3Schools Tutorial on PostgreSQL WITH

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