MS Access Rnd() Function

The Rnd() function in MS Access generates pseudo-random numbers. These are numbers that appear random but are actually determined by a mathematical algorithm. They're useful for simulations, generating test data, or adding an element of randomness to your applications.

Rnd(): Definition and Usage

It's crucial to understand that Rnd(), by itself, might produce the same "random" number repeatedly if you don't first use the Randomize() function to seed the random number generator. Randomize() initializes the generator with a more unpredictable value, making the results of subsequent Rnd() calls more varied.

Syntax and Parameter Values

The syntax for Rnd() depends on whether you want a random number between 0 (inclusive) and 1 (exclusive) or a random number within a specific range:

Syntax

-- For a random number between 0 (inclusive) and 1 (exclusive):
Rnd

-- For a random integer between lowerbound and upperbound (inclusive):
Int((upperbound - lowerbound + 1) * Rnd + lowerbound)

Examples

Generating Random Numbers in Specific Ranges

This example generates one random integer between 1 and 10 and another between 100 and 499.

Syntax

SELECT 
    Int((10 - 1 + 1) * Rnd + 1) AS RandNumBetween1and10,
    Int((499 - 100 + 1) * Rnd + 100) AS RandNumBetween100and499;
Output

RandNumBetween1and10 | RandNumBetween100and499
---------------------------------------------
(A random number 1-10)   | (A random number 100-499)
**Important Note:** The output will vary on each execution because it uses random numbers. You should use the `Randomize()` function before using `Rnd()` to ensure that you get different random numbers each time you run the query. Without `Randomize()`, you may get the same random number repeatedly.