LIMIT and OFFSET for pagination in MySQL - Step-by-Step Execution

Concept Flow - LIMIT and OFFSET for pagination

Start Query

↓

Apply OFFSET

↓

Skip OFFSET rows

↓

Apply LIMIT

↓

Return LIMIT rows

↓

End Query

The query starts, skips rows based on OFFSET, then returns a limited number of rows based on LIMIT.

Execution Sample

MySQL

SELECT * FROM employees ORDER BY id LIMIT 3 OFFSET 2;

This query returns 3 rows from the employees table, skipping the first 2 rows.

Execution Table

Step	Action	Rows Considered	Rows Skipped (OFFSET)	Rows Returned (LIMIT)
1	Start query execution	All rows in employees ordered by id	0	0
2	Apply OFFSET 2	All rows	2 rows skipped	0
3	Apply LIMIT 3	Remaining rows after offset	2	3 rows selected
4	Return result	3 rows	2 skipped	3 returned
5	End query	Result sent to client	2 skipped	3 returned

💡 Query ends after returning 3 rows following skipping 2 rows due to OFFSET

Variable Tracker

Variable	Start	After OFFSET	After LIMIT	Final
Rows considered	All rows ordered by id	All rows minus first 2	3 rows selected	3 rows returned
Rows skipped	0	2	2	2
Rows returned	0	0	3	3

Key Moments - 2 Insights

Why does OFFSET skip rows before LIMIT is applied?

OFFSET tells the database how many rows to skip first, so LIMIT then picks rows only after those skipped ones, as shown in execution_table step 2 and 3.

What happens if OFFSET is larger than total rows?

No rows remain after skipping, so LIMIT returns zero rows. This is implied in execution_table step 3 where remaining rows after offset could be zero.

Visual Quiz - 3 Questions

Look at the execution_table, how many rows are skipped at step 2?

A 3

B 2

C 0

D 5

💡 Hint

Check the 'Rows Skipped (OFFSET)' column at step 2 in execution_table.

At which step does the query decide how many rows to return?

A Step 1

B Step 5

C Step 3

D Step 2

💡 Hint

Look at the 'Action' column in execution_table where LIMIT is applied.

If LIMIT was changed to 5, how would 'Rows Returned' change after step 3?

A It would be 5

B It would be 3

C It would be 2

D It would be 0

💡 Hint

Refer to variable_tracker 'Rows returned' after LIMIT is applied.

Concept Snapshot

LIMIT and OFFSET control pagination in SQL.
OFFSET skips a number of rows first.
LIMIT sets how many rows to return after skipping.
Syntax: SELECT ... LIMIT count OFFSET skip;
Use ORDER BY to ensure consistent row order.

Full Transcript

This visual execution shows how LIMIT and OFFSET work together in a MySQL query. The query starts by ordering all rows. OFFSET skips the first specified number of rows. Then LIMIT picks the next set of rows to return. The execution table tracks these steps clearly, showing rows skipped and returned. The variable tracker follows how rows considered, skipped, and returned change step by step. Key moments clarify why OFFSET comes before LIMIT and what happens if OFFSET is too large. The quiz tests understanding of these steps by referencing the execution table and variable tracker. The snapshot summarizes the syntax and behavior for quick recall.

Practice

1. What does the LIMIT clause do in a MySQL query?

easy

A. It controls how many rows the query returns.

B. It controls the order of the rows returned.

C. It filters rows based on a condition.

D. It changes the database schema.

Solution

1. Step 1: Understand the purpose of LIMIT

   The LIMIT clause restricts the number of rows returned by a query.

2. Step 2: Compare with other options

   Ordering is done by ORDER BY, filtering by WHERE, and schema changes by DDL commands, not LIMIT.

3. Final Answer:

   It controls how many rows the query returns. -> Option A

4. Quick Check:

   LIMIT = number of rows [OK]

Hint: LIMIT sets max rows returned, like page size [OK]

Common Mistakes:

• Confusing LIMIT with ORDER BY
• Thinking LIMIT filters rows by condition
• Assuming LIMIT changes table structure

2. Which of the following is the correct syntax using the OFFSET keyword to get 10 rows starting from the 7th row in MySQL?

easy

A. SELECT * FROM table LIMIT 6, 10;

B. SELECT * FROM table LIMIT 10 OFFSET 6;

C. SELECT * FROM table OFFSET 6 LIMIT 10;

D. SELECT * FROM table LIMIT 10, 6;

Solution

1. Step 1: Understand LIMIT and OFFSET syntax

   MySQL supports both LIMIT count OFFSET offset and LIMIT offset, count syntax.

2. Step 2: Identify correct syntax for 10 rows starting at 7th row

   OFFSET 6 means skip first 6 rows, then LIMIT 10 means get next 10 rows. SELECT * FROM table LIMIT 10 OFFSET 6; uses this correctly.

3. Final Answer:

   SELECT * FROM table LIMIT 10 OFFSET 6; -> Option B

4. Quick Check:

   LIMIT count OFFSET offset = correct syntax [OK]

Hint: Use LIMIT count OFFSET offset for clarity [OK]

Common Mistakes:

• Swapping LIMIT and OFFSET values
• Using OFFSET before LIMIT incorrectly
• Confusing LIMIT offset,count with LIMIT count OFFSET offset

3. Given the table users with rows numbered by id from 1 to 20, what rows will this query return?
SELECT * FROM users ORDER BY id ASC LIMIT 5 OFFSET 10;

medium

A. Rows with id 1 to 5

B. Rows with id 6 to 10

C. Rows with id 11 to 15

D. Rows with id 16 to 20

Solution

1. Step 1: Understand OFFSET and LIMIT effect on rows

   OFFSET 10 skips first 10 rows (id 1 to 10), LIMIT 5 returns next 5 rows.

2. Step 2: Identify which rows are returned

   After skipping 10 rows, rows with id 11 to 15 are returned.

3. Final Answer:

   Rows with id 11 to 15 -> Option C

4. Quick Check:

   OFFSET 10 + LIMIT 5 = rows 11-15 [OK]

Hint: OFFSET skips rows, LIMIT picks next rows [OK]

Common Mistakes:

• Counting OFFSET as inclusive row
• Mixing up OFFSET and LIMIT order
• Assuming OFFSET starts at 1 instead of 0

4. Identify the error in this query intended to get 5 rows starting from the 3rd row:
SELECT * FROM products LIMIT OFFSET 3, 5;

medium

A. Syntax error: LIMIT should come before OFFSET without comma.

B. OFFSET cannot be used with LIMIT in this way.

C. No error; query is correct.

D. LIMIT and OFFSET are reversed in order.

Solution

1. Step 1: Check correct syntax for LIMIT and OFFSET

   Correct syntax is either LIMIT count OFFSET offset or LIMIT offset, count without the word OFFSET in the second form.

2. Step 2: Identify error in given query

   The query uses both LIMIT and OFFSET keywords together incorrectly with a comma, causing syntax error.

3. Final Answer:

   Syntax error: LIMIT should come before OFFSET without comma. -> Option A

4. Quick Check:

   LIMIT offset,count or LIMIT count OFFSET offset [OK]

Hint: Use either LIMIT offset,count or LIMIT count OFFSET offset [OK]

Common Mistakes:

• Mixing LIMIT and OFFSET keywords with commas
• Using OFFSET before LIMIT
• Adding OFFSET keyword with comma syntax

5. You want to display page 4 of a product list, showing 15 products per page, ordered by created_at descending. Which query correctly uses LIMIT and OFFSET?

hard

A. SELECT * FROM products ORDER BY created_at DESC LIMIT 45 OFFSET 15;

B. SELECT * FROM products ORDER BY created_at DESC LIMIT 60 OFFSET 15;

C. SELECT * FROM products ORDER BY created_at DESC LIMIT 15, 45;

D. SELECT * FROM products ORDER BY created_at DESC LIMIT 15 OFFSET 45;

Solution

1. Step 1: Calculate OFFSET for page 4 with 15 items per page

   Page 1 shows rows 0-14, page 2 rows 15-29, page 3 rows 30-44, so page 4 starts at offset 45.

2. Step 2: Write query with LIMIT and OFFSET

   LIMIT 15 means 15 rows per page, OFFSET 45 skips first 45 rows. SELECT * FROM products ORDER BY created_at DESC LIMIT 15 OFFSET 45; matches this.

3. Final Answer:

   SELECT * FROM products ORDER BY created_at DESC LIMIT 15 OFFSET 45; -> Option D

4. Quick Check:

   OFFSET = (page-1)*page_size = 45 [OK]

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

Common Mistakes:

• Swapping LIMIT and OFFSET values
• Calculating OFFSET incorrectly
• Using LIMIT as total rows instead of per page