FunctionsAggregate functionsAggregate Functionsavgavgavg Introduced in: v1.1 Calculates the arithmetic mean. Syntax avg(x) Arguments x — Input values. (U)Int* or Float* or Decimal Returned value Returns the arithmetic mean, otherwise returns NaN if the input parameter x is empty. Float64 Examples Basic usage SELECT avg(x) FROM VALUES('x Int8', 0, 1, 2, 3, 4, 5); ┌─avg(x)─┐ │ 2.5 │ └────────┘ Empty table returns NaN CREATE TABLE test (t UInt8) ENGINE = Memory; SELECT avg(t) FROM test; ┌─avg(x)─┐ │ nan │ └────────┘