MySQL RAND() Function

The RAND() function generates a random decimal number.

Definition and Usage

• Returns a random number between 0 (inclusive) and 1 (exclusive).
• If a seed value is provided, the function returns a repeatable sequence of random numbers for that seed.

Syntax

RAND(seed)

Parameter Values

Technical Details

• Introduced in: MySQL 4.0
• Return Value: A floating-point number between 0 and 1.

Examples

Example 1: Random decimal number (no seed)

SELECT RAND();

Output:

0.789435 (example output, varies on execution)

Example 2: Random decimal number with a seed

SELECT RAND(6);

Output:

0.197107 (always returns the same value for the seed 6)

Example 3: Random decimal number within a range

To generate a random number between 5 (inclusive) and 10 (exclusive):

SELECT RAND() * (10 - 5) + 5;

Output:

7.652934 (example output, varies on execution)

Example 4: Random integer within a range

To generate a random integer between 5 and 10 (both inclusive):

SELECT FLOOR(RAND() * (10 - 5 + 1) + 5);

Output:

8 (example output, varies on execution)

Use Cases

• Shuffling data: Use RAND() to order rows randomly.

SELECT * FROM Products
ORDER BY RAND();

• Random sampling: Retrieve random rows from a table.

SELECT * FROM Customers
ORDER BY RAND()
LIMIT 5;

• Game or lottery systems: Generate random numbers for outcomes.

Related Functions

• FLOOR(): Helps convert random decimals into integers.
• CEIL(): Rounds random numbers to the nearest greater integer.