Computes an approximate quantile of a numeric data sequence.

This function applies reservoir sampling with a reservoir size up to 8192 and a random number generator for sampling. The result is non-deterministic. To get an exact quantile, use the quantileExact function.

When using multiple quantile* functions with different levels in a query, the internal states are not combined (that is, the query works less efficiently than it could). In this case, use the quantiles function.



Alias: median.


  • level — Level of quantile. Optional parameter. Constant floating-point number from 0 to 1. We recommend using a level value in the range of [0.01, 0.99]. Default value: 0.5. At level=0.5 the function calculates median.
  • expr — Expression over the column values resulting in numeric data types, Date or DateTime.

Returned value

  • Approximate quantile of the specified level.


  • Float64 for numeric data type input.
  • Date if input values have the Date type.
  • DateTime if input values have the DateTime type.


Input table:

│   1 │
│   1 │
│   2 │
│   3 │


SELECT quantile(val) FROM t


│           1.5 │

See Also

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