LIMIT clause behavior in SQL - Step-by-Step Execution

Concept Flow - LIMIT clause behavior

Start Query Execution

↓

Retrieve All Rows

↓

Apply LIMIT Clause

↓

Return Limited Rows

↓

End Query Execution

The database runs the query, fetches all matching rows, then applies the LIMIT clause to return only the specified number of rows.

Execution Sample

SQL

SELECT * FROM employees LIMIT 3;

This query fetches all employees but returns only the first 3 rows.

Execution Table

Step	Action	Rows Retrieved	LIMIT Value	Rows Returned
1	Start query execution	0	3	0
2	Retrieve all matching rows	5	3	0
3	Apply LIMIT clause	5	3	3
4	Return limited rows	5	3	3
5	End query execution	5	3	3

💡 LIMIT 3 restricts output to first 3 rows even though 5 rows matched

Variable Tracker

Variable	Start	After Step 2	After Step 3	Final
Rows Retrieved	0	5	5	5
Rows Returned	0	0	3	3
LIMIT Value	3	3	3	3

Key Moments - 2 Insights

Why does the query return fewer rows than exist in the table?

Because the LIMIT clause restricts the number of rows returned to the specified value, as shown in execution_table step 3 where Rows Returned changes from 0 to 3.

Does LIMIT affect how many rows the database searches through?

No, the database retrieves all matching rows first (step 2), then applies LIMIT to reduce the output (step 3).

Visual Quiz - 3 Questions

Look at the execution table, how many rows are retrieved before applying LIMIT?

A 3

B 5

C 0

D All rows in the database

💡 Hint

Check the 'Rows Retrieved' column at step 2 in the execution_table.

At which step does the number of rows returned change from 0 to 3?

A Step 3

B Step 2

C Step 1

D Step 5

💡 Hint

Look at the 'Rows Returned' column in execution_table rows.

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

A It would be 3

B It would be 0

C It would be 5

D It would be more than 5

💡 Hint

Refer to the LIMIT Value and Rows Returned columns in variable_tracker.

Concept Snapshot

LIMIT clause restricts the number of rows returned by a query.
Syntax: SELECT * FROM table LIMIT number;
The database fetches all matching rows first, then returns only the first 'number' rows.
Useful to preview or paginate results.
If LIMIT exceeds available rows, all rows are returned.

Full Transcript

The LIMIT clause in SQL controls how many rows a query returns. When a query runs, the database first finds all rows that match the query conditions. Then, it applies the LIMIT clause to return only the specified number of rows. For example, if LIMIT 3 is used, only the first 3 rows are returned even if more rows match. This helps to limit output size and is useful for pagination or previews. The execution table shows that all rows are retrieved first, then limited before returning results.