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Categories: Math, Aggregate

STDDEV

Returns the standard deviation of non-NULL values in a column with a numeric data type. If all records inside a group are NULL, returns NULL.

Syntax​

STDDEV(col_name NUMERIC) → DOUBLE​

  • col_name: The name of the column for which to return the standard deviation. The values in the column must be numbers, such as INT, DOUBLE, or FLOAT.

Examples

STDDEV example 
SELECT STDDEV(tip_amount) FROM Samples."samples.dremio.com"."NYC-taxi-trips";
-- 2.2596650338662974
STDDEV example: Window function with sliding window frame 
SELECT city, state, pop, STDDEV(pop)
  OVER (PARTITION BY state ORDER BY city ROWS BETWEEN 1 PRECEDING AND 2 FOLLOWING)
FROM Samples."samples.dremio.com"."zips.json";
-- city, state, pop, EXPR$3
-- 98791, AK, 5345, 6476.127649555198
-- AKHIOK, AK, 13309, 6102.649479256257
-- AKIACHAK, AK, 481, 6429.897977417682
-- ...

Usage Notes​

The STDDEV function supports optional PARTITION BY, ORDER_BY, and sliding window frame subclauses. See Window Functions for more information and syntax.