1Z0-071 Joining Multiple Tables

Question 1

Which JOIN type returns all rows from the left table and matching rows from the right table, with NULLs for non-matches?

Accepted Answer

LEFT OUTER JOIN

Answer

LEFT OUTER JOIN returns all rows from the left table and matched rows from the right; unmatched right columns are NULL.

Question 2

What is the result of a CROSS JOIN between a table with 4 rows and a table with 3 rows?

Accepted Answer

12 rows

Answer

A CROSS JOIN (Cartesian product) returns every combination, so 4 × 3 = 12 rows.

Question 3

Which SQL syntax represents an ANSI-standard INNER JOIN?

Accepted Answer

SELECT * FROM a JOIN b ON a.id = b.id

Answer

The ANSI JOIN syntax uses the JOIN keyword with an ON clause to specify the join condition.

Question 4

What is a NATURAL JOIN in Oracle SQL?

Accepted Answer

A join that uses all columns with the same name in both tables

Answer

NATURAL JOIN automatically joins tables on all columns that share the same name and compatible data type.

Question 5

Which clause in a JOIN allows you to specify a single common column name without a table prefix?

Accepted Answer

USING

Answer

The USING clause specifies a common column by name, and that column cannot be prefixed with a table alias.

1Z0-071 - Oracle Database SQL Certified Associate Practice Test