UNION combining result sets in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

SQL

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

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

AUNION

BJOIN

CINTERSECT

DWHERE

Attempts:

3 left

💡 Hint

Common Mistakes

Using JOIN instead of UNION causes syntax errors.

Using WHERE does not combine result sets.

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

2fill in blank

medium

Complete the code to combine two queries including duplicates.

SQL

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

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AUNION ALL

BEXCEPT

CINTERSECT

DUNION

Attempts:

3 left

💡 Hint

Common Mistakes

Using UNION removes duplicates unintentionally.

Using INTERSECT or EXCEPT changes the result set meaning.

UNION ALL combines results including duplicates.

3fill in blank

hard

Fix the error in combining two queries selecting different columns.

SQL

SELECT id, name FROM products [1] SELECT product_id FROM sales;

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AUNION DISTINCT

BUNION ALL

CJOIN

DUNION

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to UNION queries with different column counts causes errors.

Using JOIN instead of UNION changes the query meaning.

Both queries must select the same number of columns with compatible types for UNION to work.

4fill in blank

hard

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

SQL

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

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 causes syntax errors.

Using GROUP BY instead of ORDER BY changes the result.

Use UNION to combine and ORDER BY to sort the final result.

5fill in blank

hard

Fill all three blanks to combine two queries selecting product names and prices, including duplicates, and order by price descending.

SQL

SELECT [1], [2] FROM store1 [3] SELECT product_name, price FROM store2 ORDER BY price DESC;

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

Aproduct_name

Bprice

CUNION ALL

DUNION

Attempts:

3 left

💡 Hint

Common Mistakes

Selecting different columns in each query causes errors.

Using UNION removes duplicates unintentionally.

Select the same columns product_name and price from both tables, use UNION ALL to include duplicates, and order by price descending.