Categories:

Aggregate functions (Linear Regression) , Window functions

# REGR_SLOPEÂ¶

Returns the slope of the linear regression line for non-null pairs in a group. It is computed for non-null pairs using the following formula:

`COVAR_POP(x,y) / VAR_POP(x)`

Where `x` is the independent variable and `y` is the dependent variable.

## SyntaxÂ¶

Aggregate function

```REGR_SLOPE(y, x)
```

Window function

```REGR_SLOPE(y, x) OVER ( [ PARTITION BY <expr3> ] )
```

## ArgumentsÂ¶

`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.

## ReturnsÂ¶

The data type of the returned value is FLOAT.

## Usage notesÂ¶

• DISTINCT is not supported for this function.

• When used as a window function:

• This function does not support:

• ORDER BY sub-clause in the OVER() clause.

• Window frames.

## ExamplesÂ¶

```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_slope(v, v2) from aggr group by k;

---+-------------------+
k | regr_slope(v, v2) |
---+-------------------+
1 | [NULL]            |
2 | 0.831408776       |
---+-------------------+
```
Language: English