LIMIT clause behavior in SQL

Introduction

The LIMIT clause helps you get only a certain number of rows from a big list. It makes it easier to see or work with just a small part of your data.

When you want to see the first 5 customers from a large customer list.

When you only need the top 10 highest scores from a game leaderboard.

When testing queries and you want to check a few rows instead of the whole table.

When showing search results page by page, like showing 20 results at a time.

Syntax

SQL

SELECT column1, column2 FROM table_name LIMIT number_of_rows;

The number_of_rows tells how many rows you want to get.

LIMIT is usually placed at the end of the SELECT statement.

Examples

Gets the first 3 rows from the employees table.

SQL

SELECT * FROM employees LIMIT 3;

Gets the first 5 users with their name and age.

SQL

SELECT name, age FROM users LIMIT 5;

Gets only the first product name from the products table.

SQL

SELECT product_name FROM products LIMIT 1;

Sample Program

This creates a small fruits table, adds 4 fruits, then selects only the first 2 rows using LIMIT.

SQL

CREATE TABLE fruits (id INT, name VARCHAR(20));
INSERT INTO fruits VALUES (1, 'Apple'), (2, 'Banana'), (3, 'Cherry'), (4, 'Date');
SELECT * FROM fruits LIMIT 2;

Important Notes

LIMIT does not guarantee order unless you use ORDER BY before it.

If you want to skip some rows and then get rows, use OFFSET with LIMIT.

Some SQL databases may use different syntax for LIMIT (like TOP in SQL Server).

Summary

LIMIT helps get a small number of rows from a query result.

It is useful for previewing data or paginating results.

Always use ORDER BY if you want consistent row order with LIMIT.

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