rand #

Returns a pseudo-random UInt32 number, uniformly distributed among all UInt32 values.
Uses a linear congruential generator.
Syntax

rand([x])

Parameter

• x — An expression that evaluates to any supported data type. The result value will be discarded, but if the function is called multiple times within a query, the expression itself can be used to bypass common subexpression elimination. Optional parameter.

Return value

• Pseudo-random UInt32 number. Type: UInt32

Example

SELECT rand(), rand(number) FROM numbers(2);

┌─rand()─────┬─rand(number)─┐ 
│ 3882830473 │ 2236253349   │ 
│ 4122795699 │ 3720179576   │ 
└────────────┴──────────────┘

rand64 #

Returns a pseudo-random UInt64 number, uniformly distributed among all UInt64 values.
Uses a linear congruential generator.
Syntax

rand64([x])

Parameter

• x — An expression that evaluates to any supported data type. The result value will be discarded, but if the function is called multiple times within a query, the expression itself can be used to bypass common subexpression elimination. Optional parameter.

Return value

• Pseudo-random UInt64 number. Type: UInt64

Example

SELECT rand64(), rand64(number) FROM numbers(2);

┌─rand64()────────────┬─rand64(number)───────┐ 
│ 4216084906413806748 │ 17404981640646529534 │ 
│ 874879808660605772  │ 941470430861381566   │ 
└─────────────────────┴──────────────────────┘

randConstant #

Generates a constant column with random values.
Syntax

randConstant([x])

Parameter

• x — An expression that evaluates to any supported data type. The result value will be discarded, but if the function is called multiple times within a query, the expression itself can be used to bypass common subexpression elimination. Optional parameter.

Return value

• Pseudo-random number. Type: UInt32.

Example

SELECT rand(), rand(1), rand(number), randConstant(), randConstant(1), randConstant(number) 
FROM numbers(3)

┌─rand()─────┬─rand(1)────┬─rand(number)─┬─randConstant()─┬─randConstant(1)─┬─randConstant(number)─┐ 
│ 1617218167 │ 3030783952 │ 3660442590   │ 3335999329     │ 1508515848      │ 1880875990           │ 
│ 432450540  │ 2987789840 │ 653572307    │ 3335999329     │ 1508515848      │ 1880875990           │ 
│ 3698169875 │ 79826010   │ 458167070    │ 3335999329     │ 1508515848      │ 1880875990           │ 
└────────────┴────────────┴──────────────┴────────────────┴─────────────────┴──────────────────────┘