Question

The ID column in the CLIENT table that corresponds to the CLIENT_ID column of the ORDER table contains null values for rows that need to be displayed. Which type of join should you use to display the data?

a.Self join
b.Nonequi-Join
c.Equijoin
d.Outer join

Answer 1

To include all records from the CLIENT table even if there are nulls in the corresponding CLIENT_ID column of the ORDER table, an outer join should be used.

Step-by-step explanation:

To display data from the CLIENT table where the ID column corresponds to the CLIENT_ID column of the ORDER table, including rows where the ID may be null, you should use an outer join. An outer join will include all records from both tables, even if there is no match between the columns being joined. In this case, if you want to include all clients regardless of whether they have placed an order, a left outer join (from the perspective of the CLIENT table) would be the appropriate choice. Conversely, if you want to include all orders, even those not matched to a client, you would use a right outer join. If you wish to have all records from both tables with nulls for non-matching entries on either side, a full outer join would be used.