rand ↗

Use the rand() function to generate a pseudo-random floating-point number between 0 (inclusive) and 1 (exclusive).

Syntax

rand()

Parameters

This function takes no parameters.

Returns

Type: float

Description: The rand() function returns a pseudo-random floating-point number in the range 0, 1). Each invocation produces a different random value.

Usage notes

  • Input type: XQL doesn't support NaN or infinite values as input and these value types also can not be returned.
  • No Arguments: The rand() function takes no parameters and generates a new random value each time it is called.
  • Range: The returned value is always ≥ 0.0 and < 1.0.
  • Non-Deterministic: Each call to rand() produces a different value. Results are not reproducible across query executions.
  • Scaling: To generate random numbers in a different range, multiply the result by the desired range and add an offset. For example, add(multiply(rand(), 100), 1) generates a random number between 1 and 101.
  • Common Use Cases: This function is typically used within the alter stage for random sampling, generating test data, randomized ordering, and probabilistic analysis.

Examples

Example 1: Generate random values for each record

Goal: Add a random value to each record in the dataset.

XQL code:

config timeframe = 1d
| dataset = sample_xql_raw
| alter random_val = rand()
| fields event_id, random_val
| limit 3

Explanation: This query generates a random floating-point number between 0 and 1 for each record and stores it in random_val. Each record receives a different random value.

Output:

EVENT_ID RANDOM_VAL
101 0.73214
102 0.15892
103 0.94501

Example 2: Random sampling of records

Goal: Randomly sample approximately 50% of records from the dataset.

XQL code:

config timeframe = 1d
| dataset = sample_xql_raw
| alter sample_flag = rand()
| filter sample_flag < 0.5
| fields event_id, source_name
| limit 5

Explanation: This query assigns a random value to each record, then filters to keep only records where the random value is less than 0.5, effectively sampling approximately 50% of the data.

Output:

EVENT_ID SOURCE_NAME
102 server-01
104 server-03
107 server-02
109 server-01
111 server-03

Example 3: Generate random integers in a specific range

Goal: Generate random integers between 1 and 100 for each record.

XQL code:

config timeframe = 1d
| dataset = sample_xql_raw
| alter random_int = to_integer(add(multiply(rand(), 100), 1))
| fields event_id, random_int
| limit 3

Explanation: This query scales the random value from [0, 1) to [1, 101) by multiplying by 100 and adding 1, then converts to an integer using to_integer() to produce whole numbers between 1 and 100.

Output:

EVENT_ID RANDOM_INT
101 47
102 83
103 12