Database Management System When R is left outer joined with

Database Management System

When R is left outer joined with S, what is true about the resulting set, T?

a. T inlcudes all tuples from R, matching tuples from S and null values where there was no matching S tuple.

b. It will include all of the rows in R, matching records in S and pad null on the left side of T.

c. All of the values from R will be followed by matching values from S.

d. All of the values from S will be produced with matching values from R and null padding in S.

Solution

Please follow the data and description :

LEFT OUTER JOIN :

A LEFT JOIN or LEFT OUTER JOIN is a result that gives all the rows from the left table with the matched rows from both the tables respectivley. When a row in the left table has no matching rows in the right table, then the associated result set row contains null values for all select list columns coming from the right table.

So the answer is OPTION A (T inlcudes all tuples from R, matching tuples from S and null values where there was no matching S tuple.).

Hope this is helpful.