VARIANCE
A synonym for VAR_POP: returns the population variance.
MySQL 8.1
VARIANCE(expr)Parameters
- exprDOUBLE
- Numeric expression
Return value
A floating-point number (DOUBLE); NULLs are ignored; 0 for a single value, NULL for an empty set
Examples
VARIANCE equals VAR_POP
MySQL 8.1
SELECT VARIANCE(x) AS variance,
VAR_POP(x) AS population,
VAR_SAMP(x) AS sample
FROM (
SELECT 1 AS x
UNION ALL
SELECT 2
UNION ALL
SELECT 3
UNION ALL
SELECT 4
) AS t;Price variance by category
MySQL 8.1
SELECT category,
ROUND(VARIANCE(price), 2) AS price_variance
FROM products
GROUP BY category;Details
In PostgreSQL, VARIANCE calculates the sample variance, like VAR_SAMP. To make the result independent of the DBMS, write VAR_POP or VAR_SAMP explicitly.