RAND

Syntax

SQL

RAND ( [seed] )

Arguments

seed: any valid numerical value.

Return type

A random float or double between 0 and 1.0.

Examples

Note that the value of RAND() is not a constant - it is a sequence of random values. This sequence is restarted for each block of rows. If it happens to restart in a consistent way, then the output of RAND() may also be consistent. The order in which rows are processed is dependent on their position on disk. In the following examples, the values in the RAND() and RAND(1234) columns differ across calls.

SQL

CREATE TABLE randos (i bigint primary key);

INSERT INTO randos VALUES (1), (2), (3), (4);

SQL

SELECT i, RAND(), RAND(1234) FROM randos;
+---+---------------------+-----------------------+
| i | RAND()              | RAND(1234)            |
+---+---------------------+-----------------------+
| 3 | 0.43534220433377946 |    0.9908611655094324 |
| 1 | 0.25176617397465795 |   0.43105064430086526 |
| 2 |  0.9479281528764876 | 0.0022682741705851717 |
| 4 |  0.8637092072853303 |    0.6844156113248886 |
+---+---------------------+-----------------------+

SQL

SELECT i, RAND(), RAND(1234) FROM randos;
+---+--------------------+---------------------+
| i | RAND()             | RAND(1234)          |
+---+--------------------+---------------------+
| 3 | 0.5683442772102069 | 0.11764372542933765 |
| 1 | 0.5781494513957496 |  0.2252007371519833 |
| 2 | 0.3707790810194105 |  0.9458377938731928 |
| 4 |  0.400653709702692 |  0.7001088226665313 |
+---+--------------------+---------------------+

SQL

SELECT i, CEIL(RAND() * 100) FROM randos;
+---+--------------------+
| i | CEIL(RAND() * 100) |
+---+--------------------+
| 3 |                 86 |
| 1 |                 52 |
| 2 |                 54 |
| 4 |                 92 |
+---+--------------------+

SQL

SELECT i FROM randos ORDER BY RAND();
+---+
| i |
+---+
| 3 |
| 4 |
| 1 |
| 2 |
+---+