RAND (Transact-SQL)

บทความ
09/03/2024

Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics

Returns a pseudo-random float value from 0 through 1, exclusive.

Syntax

RAND ( [ seed ] )

Note

This syntax is not supported by serverless SQL pool in Azure Synapse Analytics.

Arguments

seed

Is an integer expression (tinyint, smallint, or int) that gives the seed value. If seed isn't specified, the SQL Server Database Engine assigns a seed value at random. For a specified seed value, the result returned is always the same.

Return types

float

Remarks

Repetitive calls of RAND() with the same seed value return the same results.

For one connection, if RAND() is called with a specified seed value, all subsequent calls of RAND() produce results based on the seeded RAND() call. For example, the following query always returns the same sequence of numbers.
```
SELECT RAND(100), RAND(), RAND();
```
When you use the RAND() function in an UPDATE or INSERT query, all affected rows get the same value.

Examples

The following example produces four different random numbers generated by the RAND() function.

DECLARE @counter SMALLINT;

SET @counter = 1;

WHILE @counter < 5
BEGIN
    SELECT RAND() Random_Number
    SET @counter = @counter + 1
END;
GO

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