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WorksheetsJoins & Testing Quiz
Total questions: 15
Worksheet time: 8mins
Name
Class
Date
1.
What does a JOIN clause do in SQL?
a)
Sorts rows
b)
Deletes rows
c)
Combines tables
d)
Creates indexes
2.
True or False: An INNER JOIN returns only matching rows from both tables.
a)
True
b)
False
3.
A table must have a (a) key to enforce row uniqueness.
4.
Which keyword is used to refer to a table alias?
a)
AS
b)
BY
c)
ON
d)
WITH
5.
Which JOIN keeps all rows from the left table and matches from the right?
a)
INNER
b)
FULL OUTER
c)
LEFT
d)
RIGHT
6.
Which clause connects tables based on a shared column?
a)
GROUP BY
b)
ON
c)
USING
d)
HAVING
7.
Which JOIN returns all rows, matching or not, from both tables?
a)
INNER
b)
FULL OUTER
c)
LEFT
d)
CROSS
8.
Why are table aliases commonly used in SQL joins?
a)
To create indexes
b)
To remove duplicates
c)
To shorten table names
d)
To change column types
9.
True or False: You can JOIN on multiple columns using AND.
a)
True
b)
False
10.
Which keyword is used to filter grouped results?
a)
WHERE
b)
FILTER
c)
HAVING
d)
ORDER BY
11.
Which JOIN keeps all rows from the right table, matching or not?
a)
LEFT
b)
RIGHT
c)
FULL OUTER
d)
CROSS
12.
Which test ensures data hasn't unexpectedly increased or decreased after a JOIN?
a)
Key test
b)
Metric test
c)
Syntax check
d)
Relationship check
13.
SELECT * FROM A JOIN B USING (id) requires what condition?
a)
Different key names
b)
Matching key names
c)
Multiple keys
d)
No keys
14.
Which test checks if every row in a table has a unique ID?
a)
Column test
b)
Metric test
c)
Primary key test
d)
Row count test
15.
What is the risk of skipping metric conservation tests?
a)
Data formatting
b)
Visual errors
c)
Data loss or duplication
d)
Too many columns
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