Categories:

Aggregate functions (Linear Regression) , Window functions

REGR_AVGY

Returns the average of the dependent variable for non-null pairs in a group, where x is the independent variable and y is the dependent variable.

Syntax

Aggregate function

REGR_AVGY(y, x)
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Window function

REGR_AVGY(y, x) OVER ( [ PARTITION BY <expr3> ] )
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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);
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select k, regr_avgy(v, v2) from aggr group by k;

---+------------------+
 k | regr_avgy(v, v2) |
---+------------------+
 1 | [NULL]           |
 2 | 20               |
---+------------------+
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Language: English