LIMIT clause behavior in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select only the first 5 rows from the table.

SQL

SELECT * FROM employees [1] 5;

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

AORDER BY

BLIMIT

CWHERE

DGROUP BY

Attempts:

3 left

💡 Hint

Common Mistakes

Using WHERE instead of LIMIT to restrict rows.

Using ORDER BY to limit rows, which only sorts data.

The LIMIT clause restricts the number of rows returned by the query. Here, it limits the output to 5 rows.

2fill in blank

medium

Complete the code to select 3 rows starting from the 6th row.

SQL

SELECT * FROM products [1] 3 OFFSET 5;

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

ALIMIT

BWHERE

CGROUP BY

DORDER BY

Attempts:

3 left

💡 Hint

Common Mistakes

Using OFFSET without LIMIT, which returns all rows after the offset.

Using WHERE to filter rows by position, which is not valid.

The LIMIT clause specifies how many rows to return, and OFFSET skips the first rows. Here, it returns 3 rows starting after skipping 5.

3fill in blank

hard

Fix the error in the query to correctly limit results to 10 rows.

SQL

SELECT name, age FROM users [1] 10 OFFSET 0;

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

AORDER BY

BWHERE

CGROUP BY

DLIMIT

Attempts:

3 left

💡 Hint

Common Mistakes

Using WHERE to limit rows, which filters by condition, not count.

Using ORDER BY without LIMIT, which only sorts rows.

The LIMIT clause is used to restrict the number of rows returned. OFFSET 0 means start from the first row.

4fill in blank

hard

Fill both blanks to select 4 rows starting from the 3rd row.

SQL

SELECT * FROM orders [1] 4 [2] 2;

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

ALIMIT

BOFFSET

CWHERE

DORDER BY

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping LIMIT and OFFSET positions.

Using WHERE to skip rows, which is invalid.

LIMIT sets how many rows to return, and OFFSET sets how many rows to skip before starting.

5fill in blank

hard

Fill all three blanks to select the top 5 employees ordered by salary descending, skipping the first 10.

SQL

SELECT * FROM employees [1] salary DESC [2] 5 [3] 10;

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

AORDER BY

BLIMIT

COFFSET

DGROUP BY

Attempts:

3 left

💡 Hint

Common Mistakes

Placing LIMIT before ORDER BY, which causes syntax errors.

Using GROUP BY instead of ORDER BY for sorting.

ORDER BY sorts the rows by salary descending. LIMIT restricts to 5 rows, and OFFSET skips the first 10 rows.

Practice

1. What does the LIMIT clause do in an SQL query?

easy

A. It restricts the number of rows returned by the query.

B. It sorts the rows in ascending order.

C. It groups rows based on a column.

D. It deletes rows from the table.

Solution

1. Step 1: Understand the purpose of LIMIT

   The LIMIT clause is used to restrict the number of rows returned by a query.

2. Step 2: Compare with other options

   Sorting is done by ORDER BY, grouping by GROUP BY, and deleting by DELETE statement, not LIMIT.

3. Final Answer:

   It restricts the number of rows returned by the query. -> Option A

4. Quick Check:

   LIMIT = restrict rows [OK]

Hint: LIMIT controls how many rows you get back [OK]

Common Mistakes:

• Confusing LIMIT with ORDER BY
• Thinking LIMIT deletes rows
• Mixing LIMIT with GROUP BY

2. Which of the following is the correct syntax to get the first 5 rows from a table named employees?

easy

A. SELECT * FROM employees LIMIT 5;

B. SELECT * FROM employees TOP 5;

C. SELECT * FROM employees FETCH FIRST 5 ROWS;

D. SELECT * FROM employees WHERE LIMIT = 5;

Solution

1. Step 1: Identify correct LIMIT syntax

   The standard SQL syntax to limit rows is using LIMIT followed by the number, e.g., LIMIT 5.

2. Step 2: Check other options

   TOP 5 is SQL Server syntax, FETCH FIRST 5 ROWS is standard SQL but typically requires 'ONLY', and WHERE LIMIT = 5 is invalid.

3. Final Answer:

   SELECT * FROM employees LIMIT 5; -> Option A

4. Quick Check:

   LIMIT 5 = first 5 rows [OK]

Hint: Use LIMIT number after FROM to restrict rows [OK]

Common Mistakes:

• Using TOP instead of LIMIT in standard SQL
• Misplacing LIMIT inside WHERE clause
• Using FETCH without OFFSET incorrectly

3. Given the table products with rows:
id | name
1 | Apple
2 | Banana
3 | Cherry
4 | Date
5 | Elderberry
What is the result of the query:
SELECT name FROM products ORDER BY id DESC LIMIT 3;?

medium

A. ["Apple", "Banana", "Cherry"]

B. ["Elderberry", "Date", "Cherry"]

C. ["Cherry", "Date", "Elderberry"]

D. ["Date", "Elderberry", "Cherry"]

Solution

1. Step 1: Understand ORDER BY id DESC

   Ordering by id descending means rows are sorted from highest id to lowest: 5,4,3,2,1.

2. Step 2: Apply LIMIT 3

   LIMIT 3 returns the first 3 rows after sorting: ids 5,4,3 which correspond to Elderberry, Date, Cherry.

3. Final Answer:

   ["Elderberry", "Date", "Cherry"] -> Option B

4. Quick Check:

   ORDER BY DESC + LIMIT 3 = top 3 highest ids [OK]

Hint: ORDER BY DESC then LIMIT gets top N rows [OK]

Common Mistakes:

• Ignoring ORDER BY and taking first rows as is
• Mixing ascending and descending order
• Confusing LIMIT number with offset

4. What is wrong with this query?
SELECT * FROM orders LIMIT;

medium

A. LIMIT only works with numeric columns.

B. LIMIT cannot be used without ORDER BY.

C. LIMIT must be placed before FROM clause.

D. LIMIT requires a number to specify how many rows to return.

Solution

1. Step 1: Check LIMIT syntax

   LIMIT must be followed by a number indicating how many rows to return.

2. Step 2: Validate other options

   LIMIT can be used without ORDER BY, it comes after FROM, and works on any query regardless of column types.

3. Final Answer:

   LIMIT requires a number to specify how many rows to return. -> Option D

4. Quick Check:

   LIMIT needs a number [OK]

Hint: Always put a number after LIMIT [OK]

Common Mistakes:

• Omitting the number after LIMIT
• Thinking ORDER BY is mandatory with LIMIT
• Placing LIMIT before FROM

5. You want to show page 3 of a product list, showing 10 products per page, ordered by price ascending. Which query correctly uses LIMIT and OFFSET to achieve this?

hard

A. SELECT * FROM products ORDER BY price ASC LIMIT 10 OFFSET 30;

B. SELECT * FROM products ORDER BY price ASC LIMIT 30 OFFSET 10;

C. SELECT * FROM products ORDER BY price ASC LIMIT 10 OFFSET 20;

D. SELECT * FROM products ORDER BY price ASC LIMIT 20 OFFSET 10;

Solution

1. Step 1: Calculate OFFSET for page 3 with 10 rows per page

   Page 1 shows rows 0-9, page 2 shows 10-19, so page 3 starts at offset 20.

2. Step 2: Use LIMIT 10 to get 10 rows for the page

   LIMIT 10 returns 10 rows starting from OFFSET 20.

3. Final Answer:

   SELECT * FROM products ORDER BY price ASC LIMIT 10 OFFSET 20; -> Option C

4. Quick Check:

   Page 3 offset = (3-1)*10 = 20 [OK]

Hint: OFFSET = (page-1)*rows, LIMIT = rows per page [OK]

Common Mistakes:

• Using wrong OFFSET calculation
• Mixing LIMIT and OFFSET values
• Forgetting ORDER BY for consistent paging