What is update?
Update is a SQLite command that allows you to change data in your database. You can use the
UPDATE command to change data in one or more columns of a single row, multiple rows, or all rows in a table.
UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition;
UPDATE customers SET name='Liam' WHERE id=1;
Update multiple columns
UPDATE customers SET name='Liam', city='New York' WHERE id=1;
Update from select
In the example below, the has_order column is updated if the select returns the value 1.
UPDATE customers SET has_orders = (SELECT 1 FROM orders WHERE customers.id = orders.customer_id) WHERE id is not null;
Update from subquery
In the example below, the update is done if the condition after the WHERE clause is met based on a subquery.
UPDATE customers SET has_orders = 1 WHERE id in (SELECT distinct customer_id FROM orders);