Applies to: ✅ Data 360 SQL ✅ Tableau Hyper API
Computes the population skewness of input values. Skewness measures the asymmetry of a distribution: positive values indicate a longer right tail, negative values indicate a longer left tail, and zero indicates a symmetric distribution.
Syntax
skewness_pop(<expression>)
Arguments
Required
<expression>: An expression of any numerical type.
Returns
Returns a double precision value.
Returns NULL when fewer than three non-null input values are provided or when all non-null values are identical.
Considerations
- Use
SKEWNESS_POPwhen the data is the complete population of interest (for example, every order in a closed quarter). UseSKEWNESS_SAMPwhen the data is a sample drawn from a larger population. - Computes the Fisher–Pearson population coefficient of skewness, without bias correction.
- For large row counts,
SKEWNESS_POPandSKEWNESS_SAMPconverge. - Ignores NULL inputs. Any NaN or infinite input propagates to a NaN result.
Examples
Calculate Population Skewness
Check whether last quarter's order totals are skewed toward a few large purchases.
SELECT skewness_pop(order_total) AS order_total_skew
FROM orders
WHERE order_quarter = '2026-Q1';
Skewness by Group
Compare the asymmetry of score distributions across cohorts.
SELECT cohort, skewness_pop(score) AS score_skew
FROM exam_results
GROUP BY cohort;