Exercise

LEFT join

An INNER JOIN shows you exact matches. What about when you want to compare all the values in one table with another, to see which rows match? That's when you can use a LEFT JOIN.

A LEFT JOIN will return ALL rows in the first table, and any matching rows in the right table. If there aren't any matches in the right table for a particular row, then a NULL is returned. This quickly lets you assess the gaps in your data, and how many you have.

Instructions

100 XP

Complete the LEFT JOIN, returning all rows from the specified columns from invoiceline and any matches from invoice.

Take Hint (-30 XP)