- Categories:
Aggregate functions (Linear Regression) , Window functions
REGR_AVGX¶
Returns the average of the independent variable for non-null pairs in a group, where x
is the independent variable and y
is the dependent variable.
Syntax¶
Aggregate function
REGR_AVGX(y, x)
Window function
REGR_AVGX(y, x) OVER ( [ PARTITION BY <expr3> ] )
Arguments¶
y
The dependent variable. This must be an expression that can be evaluated to a numeric type.
x
The independent variable. This must be an expression that can be evaluated to a numeric type.
expr3
This is the optional expression used to group rows into partitions.
Important
Note the order of the arguments; the dependent variable is first.
Usage notes¶
DISTINCT is not supported for this function.
In order for a row to be included in the average, BOTH the x and y values must be non-NULL.
When this function is called as a window function, it does not support:
An ORDER BY clause within the OVER clause.
Explicit window frames.
Examples¶
CREATE OR REPLACE TABLE aggr(k int, v decimal(10,2), v2 decimal(10, 2));
INSERT INTO aggr VALUES(1, 10, NULL);
INSERT INTO aggr VALUES(2, 10, 11), (2, 20, 22), (2, 25, NULL), (2, 30, 35);
SELECT k, REGR_AVGX(v, v2) FROM aggr GROUP BY k;
---+------------------+
k | regr_avgx(v, v2) |
---+------------------+
1 | [NULL] |
2 | 22.666666667 |
---+------------------+