SQL Fundamentals (Data+) Quiz: SELECT, JOIN & GROUP BY

1. What is the correct syntax for a basic SELECT statement?

SELECT FROM table WHERE column

SELECT column FROM table

FROM table SELECT column

SELECT table.column FROM

Submit

3. What does SUM() aggregate function calculate?

Count of rows

Total of numeric values in a column

Average value

Maximum value

4. Which keyword combines results from multiple SELECT statements?

MERGE

COMBINE

UNION

APPEND

5. What is the purpose of the LIMIT clause?

Restrict the number of rows returned

Filter rows by condition

Group results

Sort results

6. A FULL OUTER JOIN returns rows that match in which scenario?

Only the left table

Only the right table

Both tables or either table

Neither table

7. In a GROUP BY query, which columns must be in the SELECT list?

All columns from the table

Only grouped columns or aggregate functions

Any column from any table

Columns with non-NULL values only

8. What does ORDER BY do in a SELECT statement?

Groups rows by column values

Sorts result rows in ascending or descending order

Filters rows based on conditions

Limits the number of rows returned

9. Which aggregate function returns the average of numeric values?

MEAN()

AVERAGE()

AVG()

MEDIAN()

10. A RIGHT JOIN returns all rows from which table?

The left table

The right table

Both tables

Neither table

11. Which SQL clause is used to filter rows before aggregation in a GROUP BY query?

WHERE

HAVING

FILTER

AGGREGATE

12. In SQL, which aggregate function returns the highest value in a column?

HIGH()

TOP()

MAX()

LARGEST()

13. What does the UNION operator do?

Combines rows from two queries with duplicates

Combines rows from two queries, removing duplicates

Joins two tables on a condition

Merges columns from two tables

14. Which clause must follow GROUP BY when filtering aggregated data?

WHERE

ORDER BY

HAVING

LIMIT

15. What does a CROSS JOIN produce?

Cartesian product of two tables

Only matching rows

Rows where values are equal

A filtered subset

16. Which function counts non-NULL values in a column?

SUM()

COUNT()

TOTAL()

ROWS()

17. What is the primary purpose of the GROUP BY clause?

Sort results alphabetically

Combine rows into groups for aggregation

Filter individual rows

Join multiple tables together

18. Which JOIN type returns all rows from the left table and matching rows from the right?

INNER JOIN

RIGHT JOIN

LEFT JOIN

FULL JOIN

19. In a SELECT statement, which keyword removes duplicate rows from results?

UNIQUE

DISTINCT

REMOVE

NODUPLICATE

20. What does an INNER JOIN return?

All rows from both tables

Only matching rows from both tables

All rows from the left table

All rows from the right table

SQL Quiz: Can You Master SELECT, JOIN & GROUP BY?