regr_sxx
aggregate function
Applies to: Databricks SQL Databricks Runtime 11.3 LTS and above
Returns the sum of squares of the xExpr
values of a group where xExpr
and yExpr
are NOT NULL
.
Syntax
regr_sxx( [ALL | DISTINCT] yExpr, xExpr) [FILTER ( WHERE cond ) ]
This function can also be invoked as a window function using the OVER
clause.
Arguments
yExpr
: A numeric expression, the dependent variable.xExpr
: A numeric expression, the independent variable.cond
: An optional Boolean expression filtering the rows used for the function.
Returns
The result type is DOUBLE
.
Any nulls within the group are ignored. If a group is empty or consists only of nulls, the result is NULL
.
If DISTINCT
is specified, the result is computed after duplicates are removed.
regr_sxx(y, x)
is a synonym for regr_count(y, x) * var_pop(x)
.
Examples
> SELECT typeof(regr_sxx(y, x)) FROM VALUES (1, 2), (2, 3), (2, 3), (null, 4), (4, null) AS T(y, x);
0.6666666666666666