RAND()¶
The RAND() function is used to generate a Float64 type random number between 0 and 1.
Description¶
The RAND() function is used to generate a Float64 type random number between 0 and 1. It does not accept any arguments and generates a random number that is unpredictable and non-repeating each time it is called.
If you need to randomly select data from a table, you can use the RAND() function to generate a random number, and then use ORDER BY to sort the data in the table according to this random number. For example:
-- Randomly retrieve all data from the table and sort it in a random order, the order of the query results may differ each time.
SELECT * FROM `table` ORDER BY RAND();
Syntax¶
> RAND([seed])
Arguments¶
Arguments |
Description |
|---|---|
seed |
Optional argument. It is an integer value used to specify the |
Examples¶
Example 1
mysql> SELECT RAND();
+---------------------+
| rand() |
+---------------------+
| 0.25193285156620004 |
+---------------------+
1 row in set (0.00 sec)
Example 2
CREATE TABLE Users (
ID INT PRIMARY KEY AUTO_INCREMENT,
UserName VARCHAR(255) NOT NULL,
Email VARCHAR(255));
INSERT INTO Users (UserName, Email) VALUES
('John', 'john@example.com'),
('Jane', 'jane@example.com'),
('Alice', 'alice@example.com'),
('Bob', 'bob@example.com');
-- Select a user's information randomly from the Users table.
mysql> SELECT * FROM Users ORDER BY RAND() LIMIT 1;
+------+----------+-----------------+
| id | username | email |
+------+----------+-----------------+
| 4 | Bob | bob@example.com | -- Bob's information is randomly selected.
+------+----------+-----------------+
1 row in set (0.01 sec)
-- Execute the above query again, and another user may be selected.
mysql> SELECT * FROM Users ORDER BY RAND() LIMIT 1;
+------+----------+-------------------+
| id | username | email |
+------+----------+-------------------+
| 3 | Alice | alice@example.com | -- Alice's information is randomly selected.
+------+----------+-------------------+
1 row in set (0.01 sec)
Constraints¶
MatrixOne does not currently support specifying the seed value for the RAND(seed) function (i.e., the seed parameter).