# Only - chart function

Only() returns a value if there is one and only one possible result from the aggregated data. For example, searching for the only product where the unit price =9 will return NULL if more than one product has a unit price of 9.

Syntax:

Only([{SetExpression}] [TOTAL [<fld {,fld}>]] expr)

Return data type: dual

Arguments:

Arguments

| Argument | Description |
| --- | --- |
| expr | The expression or field containing the data to be measured. |
| SetExpression | By default, the aggregation function<br>will aggregate over the set of possible records defined by the selection.<br>An alternative set of records can be defined by a set analysis<br>expression. |
| TOTAL | If the word<br>TOTAL occurs before the function<br>arguments, the calculation is made over all possible values given<br>the current selections, and not just those that pertain to the current dimensional value, that is, it disregards the chart dimensions.<br><br>By using TOTAL [&lt;fld {.fld}&gt;], where the TOTAL qualifier is followed by a list of one or more field names as a subset of the chart dimension variables, you create a subset of the total possible values.<br><br>[Defining the aggregation scope](https://help.qlik.com/en-US/sense/November2024/Subsystems/Hub/Content/Sense_Hub/ChartFunctions/define-aggregation-scope.htm) |

Tip noteUse Only() when you want a NULL result if there are multiple possible values in the sample data.

Examples and results:

Data

| Customer | Product | UnitSales | UnitPrice |
| --- | --- | --- | --- |
| Astrida | AA | 4 | 16 |
| Astrida | AA | 10 | 15 |
| Astrida | BB | 9 | 9 |
| Betacab | BB | 5 | 10 |
| Betacab | CC | 2 | 20 |
| Betacab | DD | - | 25 |
| Canutility | AA | 8 | 15 |
| Canutility | CC | - | 19 |

Examples and results

| Examples | Results |
| --- | --- |
| `<br>Only({<UnitPrice={9}>} Product)` | BB, because this is the only `Product`that has a `UnitPrice` of '9'. |
| `Only({<Product={DD}>} Customer)` | Betacab, because it is the only `Customer` selling a `Product` called 'DD'. |
| `Only({<UnitPrice={20}>} UnitSales)` | The number of `UnitSales` where `UnitPrice` is 20 is 2, because there is only one value of `UnitSales` where the `UnitPrice` =20. |
| `Only({<UnitPrice={15}>} UnitSales)` | NULL, because there are two values of `UnitSales` where the `UnitPrice` =15. |

Data used in examples:

`ProductData:` `LOAD * inline [` `Customer|Product|UnitSales|UnitPrice` `Astrida|AA|4|16` `Astrida|AA|10|15` `Astrida|BB|9|9` `Betacab|BB|5|10` `Betacab|CC|2|20` `Betacab|DD||25` `Canutility|AA|8|15` `Canutility|CC||19` `] (delimiter is '|');`

## Learn more

* [Set analysis](https://help.qlik.com/en-US/sense/November2024/Subsystems/Hub/Content/Sense_Hub/ChartFunctions/SetAnalysis/set-analysis-expressions.htm)
* [Defining the aggregation scope](https://help.qlik.com/en-US/sense/November2024/Subsystems/Hub/Content/Sense_Hub/ChartFunctions/define-aggregation-scope.htm)