Amazon Redshift will no longer support the creation of new Python UDFs starting Patch 198. Existing Python UDFs will continue to function until June 30, 2026. For more information, see the [ blog post ](https://amazonaws-china.com/blogs/big-data/amazon-redshift-python-user-defined-functions-will-reach-end-of-support-after-june-30-2026/). 

# RATIO\_TO\_REPORT window function
<a name="r_WF_RATIO_TO_REPORT"></a>

Calculates the ratio of a value to the sum of the values in a window or partition. The ratio to report value is determined using the formula:

`value of `*ratio\_expression* `argument for the current row / sum of` *ratio\_expression* `argument for the window or partition`

The following dataset illustrates use of this formula:

```
Row#	Value	Calculation	RATIO_TO_REPORT
1	2500	(2500)/(13900)	0.1798
2	2600	(2600)/(13900)	0.1870
3	2800	(2800)/(13900)	0.2014
4	2900	(2900)/(13900)	0.2086
5	3100	(3100)/(13900)	0.2230
```

The return value range is 0 to 1, inclusive. If *ratio\_expression* is NULL, then the return value is `NULL`. If a value in *partition\_expression* is unique, then function will return `1` for that value.

## Syntax
<a name="r_WF_RATIO_TO_REPORT-synopsis"></a>

```
RATIO_TO_REPORT ( ratio_expression )
OVER ( [ PARTITION BY partition_expression ] )
```

## Arguments
<a name="r_WF_RATIO_TO_REPORT-arguments"></a>

*ratio\_expression*   
An expression, such as a column name, that provides the value for which to determine the ratio. The expression must have either a numeric data type or be implicitly convertible to one.  
You cannot use any other analytic function in *ratio\_expression*.

OVER  
A clause that specifies the window partitioning. The OVER clause cannot contain a window ordering or window frame specification.

PARTITION BY *partition\_expression*   
Optional. An expression that sets the range of records for each group in the OVER clause.

## Return type
<a name="r_WF_RATIO_TO_REPORT-return-type"></a>

FLOAT8

## Examples
<a name="r_WF_RATIO_TO_REPORT-examples"></a>

The following examples use the WINSALES table. For a information about how to create the WINSALES table, see [Sample table for window function examples](c_Window_functions.md#r_Window_function_example).

The following example calculates the ratio-to-report value of each row of a seller's quantity to the total of all seller's quantities.

```
select sellerid, qty, ratio_to_report(qty) 
over()
from winsales
order by sellerid;

sellerid  qty    ratio_to_report
--------------------------------------
1         30     0.13953488372093023	
1         10     0.046511627906976744	
1         10     0.046511627906976744	
2         20     0.09302325581395349	
2         20     0.09302325581395349	
3         30     0.13953488372093023	
3         20     0.09302325581395349	
3         15     0.06976744186046512	
3         10     0.046511627906976744	
4         10     0.046511627906976744	
4         40     0.18604651162790697
```

The following example calculates the ratios of the sales quantities for each seller by partition.

```
select sellerid, qty, ratio_to_report(qty) 
over(partition by sellerid) 
from winsales;

sellerid   qty    ratio_to_report
-------------------------------------------
2          20     0.5	
2          20     0.5	
4          40     0.8	
4          10     0.2	
1          10     0.2	
1          30     0.6	
1          10     0.2	
3          10     0.13333333333333333	
3          15     0.2	
3          20     0.26666666666666666	
3          30     0.4
```