Select statement formatting

Question

I\'m trying to match up data from two tables. One is an invoices table with the date when a thing goes out and when it comes back in. The other is a line item table with each it

Answer 1

When using JOIN, always use the ON or USING (fields, ...) part of the syntax.

In this case the field name in both tables was the same, invoice_number, so USING (invoice_number) was an appropriate syntax.

If they where different names ON invoices.ID = line_item.invoice_number syntax could be used.

Multiple conditions could be used so the criteria can be used in some ways like the the WHERE criteria of SQL.