SQL Joining Multiple Tables 2

Question 1

Which join returns only rows that have matching values in both tables?

Accepted Answer

INNER JOIN

Answer

LEFT JOIN

Answer

FULL OUTER JOIN

Answer

CROSS JOIN

Question 2

A LEFT JOIN between Customers and Orders returns customers with no orders. What appears in the Orders columns for those rows?

Accepted Answer

NULL

Answer

0

Answer

Empty string

Answer

The row is excluded

Question 3

Which clause is used to specify the matching condition in a join?

Accepted Answer

ON

Answer

WHERE

Answer

HAVING

Answer

USING ONLY

Question 4

What does a CROSS JOIN produce?

Accepted Answer

The Cartesian product of both tables

Answer

Only matching rows

Answer

Only the left table's rows

Answer

Distinct rows from both tables

Question 5

Which keyword lets you join a table to itself?

Accepted Answer

Use table aliases

Answer

SELF JOIN keyword

Answer

RECURSIVE

Answer

DOUBLE JOIN

Question 6

In 'SELECT * FROM A JOIN B USING (id)', what does USING require?

Accepted Answer

A column named id in both tables

Answer

A primary key on A only

Answer

Identical row counts

Answer

A WHERE clause

Question 7

Which join returns all rows from both tables, matched where possible and NULL-filled otherwise?

Accepted Answer

FULL OUTER JOIN

Answer

INNER JOIN

Answer

LEFT JOIN

Answer

CROSS JOIN