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groupArraySample
Creates an array of sample argument values. The size of the resulting array is limited to max_size
elements. Argument values are selected and added to the array randomly.
Syntax
groupArraySample(max_size[, seed])(x)
Arguments
max_size
— Maximum size of the resulting array. UInt64.seed
— Seed for the random number generator. Optional. UInt64. Default value:123456
.x
— Argument (column name or expression).
Returned values
- Array of randomly selected
x
arguments.
Type: Array.
Examples
Consider table colors
:
┌─id─┬─color──┐
│ 1 │ red │
│ 2 │ blue │
│ 3 │ green │
│ 4 │ white │
│ 5 │ orange │
└────┴────────┘
Query with column name as argument:
SELECT groupArraySample(3)(color) as newcolors FROM colors;
Result:
┌─newcolors──────────────────┐
│ ['white','blue','green'] │
└────────────────────────────┘
Query with column name and different seed:
SELECT groupArraySample(3, 987654321)(color) as newcolors FROM colors;
Result:
┌─newcolors──────────────────┐
│ ['red','orange','green'] │
└────────────────────────────┘
Query with expression as argument:
SELECT groupArraySample(3)(concat('light-', color)) as newcolors FROM colors;
Result:
┌─newcolors───────────────────────────────────┐
│ ['light-blue','light-orange','light-green'] │
└─────────────────────────────────────────────┘