Joining tables

BigQuery supports a variety of join types that can be used to combine data from two or more tables. The most common join types are inner joins, outer joins, and self joins.

Inner joins

An inner join returns rows that match the JOIN condition from both tables. It only returns the rows where the joining condition is met on both tables. The JOIN condition is a Boolean expression that compares values in the two tables. For example, the following query joins the customers table and the orders table on the customer_id column:

SELECT customer_id, name, order_id, order_date
FROM customers
INNER JOIN orders
ON customers.customer_id = orders.customer_id

This query will return all rows from the customers table that have a matching row in the orders table. Inner joins are useful when you want to focus on the intersection of data between tables.

Outer joins

An outer join returns all rows from the left table, even if there is no matching row in the right table. The...