ROUND, CEIL, FLOOR in MySQL - Step-by-Step Execution

Concept Flow - ROUND, CEIL, FLOOR

Start with a number

↓

ROUND

↓

Round to nearest

↓

Return result

↓

End

Start with a number, pick ROUND to round normally, CEIL to round up, or FLOOR to round down, then get the result.

Execution Sample

MySQL

SELECT ROUND(4.3), CEIL(4.3), FLOOR(4.3);

This query rounds 4.3 normally, rounds it up, and rounds it down.

Execution Table

Step	Function	Input	Operation	Result
1	ROUND	4.3	Round to nearest integer	4
2	CEIL	4.3	Round up to next integer	5
3	FLOOR	4.3	Round down to previous integer	4
4	END		All functions executed	Query returns (4, 5, 4)

💡 All functions processed, query returns final rounded values.

Variable Tracker

Variable	Start	After ROUND	After CEIL	After FLOOR	Final
number	4.3	4.3	4.3	4.3	4.3
ROUND_result	N/A	4	4	4	4
CEIL_result	N/A	N/A	5	5	5
FLOOR_result	N/A	N/A	N/A	4	4

Key Moments - 3 Insights

Why does ROUND(4.3) return 4 instead of 5?

ROUND rounds to the nearest integer. Since 4.3 is closer to 4 than 5, it returns 4 (see execution_table row 1).

Why does CEIL(4.3) return 5 even though 4.3 is less than 5?

CEIL always rounds up to the next integer, so it returns 5 regardless of decimal part (see execution_table row 2).

Why does FLOOR(4.3) return 4 instead of 3?

FLOOR always rounds down to the previous integer, so it returns 4 because 4 is the greatest integer less than or equal to 4.3 (see execution_table row 3).

Visual Quiz - 3 Questions

Look at the execution_table, what is the result of CEIL(4.3) at step 2?

A 4

B 5

C 3

D 4.3

💡 Hint

Check the 'Result' column in execution_table row 2 for CEIL function.

At which step does the function round the number down?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Look for FLOOR function in execution_table which rounds down.

If the input number was 4.7, what would ROUND(4.7) return?

A 4

B 6

C 5

D 4.7

💡 Hint

ROUND rounds to nearest integer; 4.7 is closer to 5 than 4.

Concept Snapshot

ROUND(number): rounds to nearest integer.
CEIL(number): rounds up to next integer.
FLOOR(number): rounds down to previous integer.
Use these to control decimal rounding in queries.
Example: SELECT ROUND(4.3), CEIL(4.3), FLOOR(4.3);

Full Transcript

This visual shows how MySQL rounding functions work step-by-step. Starting with the number 4.3, ROUND returns 4 because it rounds to the nearest integer. CEIL returns 5 because it always rounds up. FLOOR returns 4 because it always rounds down. The execution table tracks each function's input, operation, and result. The variable tracker shows how the number changes after each function. Key moments clarify common confusions about rounding behavior. The quiz tests understanding by asking about specific steps and results. Remember, ROUND is normal rounding, CEIL is always up, and FLOOR is always down.