Syntax\n------\n\nVARIANCE(expr)\n\nDescription\n-----------\n\nReturns the population standard variance of expr. This is an extension to standard SQL. The standard SQL function VAR_POP() can be used instead.\n\nVariance is calculated by\n\n working out the mean for the set;\n for each number, subtracting the mean and squaring the result;\n* calculating the average of the resulting differences.\n\nIt is an aggregate function, and so can be used with the GROUP BY clause.\n\nVARIANCE() can be used as a window function.\n\nVARIANCE() returns NULL if there were no matching rows.\n\nExamples\n--------\n\nCREATE TABLE v(i tinyint);\n\nINSERT INTO v VALUES(101),(99);\n\nSELECT VARIANCE(i) FROM v;\n+-------------+\n| VARIANCE(i) |\n+-------------+\n|      1.0000 |\n+-------------+\n\nINSERT INTO v VALUES(120),(80);\n\nSELECT VARIANCE(i) FROM v;\n+-------------+\n| VARIANCE(i) |\n+-------------+\n|    200.5000 |\n+-------------+\n\nURL: https://mariadb.com/docs/server/reference/sql-functions/aggregate-functions/variance