Use SQL joins in PostgreSQL. At this point, we are going to create and run a query against multiple tables using join clauses, almost always inner join clauses (the default).

Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement. It’s sometimes difficult to know which SQL syntax to use when ...

If you only want to update values in table A when there are matching records in table B, then an inner join is the way to go. If you have calculations that need to vary based on optional data, the ...