`regr_avgx` aggregate function

Applies to: Databricks SQL Databricks Runtime 11.3 LTS and above

Returns the mean of xExpr calculated from values of a group where xExpr and yExpr are NOT NULL.

Syntax

regr_avgx( [ALL | DISTINCT] yExpr, xExpr) [FILTER ( WHERE cond ) ]

This function can also be invoked as a window function using the OVER clause.

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.

The result type depends on the type of xExpr:

DECIMAL(p, s): The result type is a DECIMAL(p + 4, s + 4). If the maximum precision for DECIMAL is reached the increase in scale will be limited to avoid loss of significant digits.
Otherwise, the result is a 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 average is computed after duplicates have been removed.

regr_avgx(y, x) is a synonym for avg(x) FILTER(WHERE x IS NOT NULL AND y IS NOT NULL).

SQL
> SELECT regr_avgx(y, x) FROM VALUES (1, 2), (2, 3), (2, 3), (null, 4), (4, null) AS T(y, x);
  1.6666666666666665