UNION and UNION ALL in MySQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to combine results from two tables without duplicates.

MySQL

SELECT name FROM employees [1] SELECT name FROM managers;

Drag options to blanks, or click blank then click option'

AUNION

BINTERSECT

CUNION ALL

DJOIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using UNION ALL when duplicates should be removed.

Using JOIN which combines rows differently.

The UNION keyword combines results from two queries and removes duplicates.

2fill in blank

medium

Complete the code to combine all rows from two tables, including duplicates.

MySQL

SELECT city FROM customers [1] SELECT city FROM suppliers;

Drag options to blanks, or click blank then click option'

AUNION

BUNION ALL

CINTERSECT

DEXCEPT

Attempts:

3 left

💡 Hint

Common Mistakes

Using UNION which removes duplicates.

Using INTERSECT which returns only common rows.

The UNION ALL keyword combines results from two queries and keeps all duplicates.

3fill in blank

hard

Fix the error in the code to correctly combine two SELECT queries.

MySQL

SELECT id, name FROM products [1] SELECT id, name FROM inventory;

Drag options to blanks, or click blank then click option'

AJOIN

BUNION

CUNION ALL

DWHERE

Attempts:

3 left

💡 Hint

Common Mistakes

Using JOIN which causes syntax error here.

Using WHERE which is invalid between SELECT statements.

To combine all rows including duplicates, use UNION ALL. JOIN is for combining columns, not rows.

4fill in blank

hard

Fill both blanks to combine two queries and order the results by name.

MySQL

SELECT name FROM staff [1] SELECT name FROM contractors [2] name;

Drag options to blanks, or click blank then click option'

AUNION

BORDER BY

CUNION ALL

DGROUP BY

Attempts:

3 left

💡 Hint

Common Mistakes

Placing ORDER BY before UNION.

Using GROUP BY instead of ORDER BY for sorting.

Use UNION to combine results without duplicates, then ORDER BY to sort by name.

5fill in blank

hard

Fill all three blanks to combine two queries, keep duplicates, and sort by city.

MySQL

SELECT city FROM customers [1] SELECT city FROM vendors [2] city [3];

Drag options to blanks, or click blank then click option'

AUNION ALL

BORDER BY

CASC

DGROUP BY

Attempts:

3 left

💡 Hint

Common Mistakes

Using UNION instead of UNION ALL which removes duplicates.

Using GROUP BY which groups rows instead of sorting.

Use UNION ALL to keep duplicates, then ORDER BY city ASC to sort cities alphabetically.