This section covers areas of aggregation that don't fit within the other sections of the documentation.
Default Aggregation Function
When columns are dragged to the Values section of the Columns Tool Panel they are assigned the sum
aggregation function by default. The default aggregation function can be overridden on a per-column basis using the defaultAggFunc
column property.
<ag-grid-vue
:columnDefs="columnDefs"
/* other grid options ... */>
</ag-grid-vue>
this.columnDefs = [
{
field: 'gold',
// allows column to be dragged to the 'Values` section of the Columns Tool Panel
enableValue: true,
// use 'avg' as the default agg func instead of 'sum'
defaultAggFunc: 'avg',
},
];
The following example demonstrates overriding the default agg function. Note the following:
- The Gold column is configured with
defaultAggFunc
set toavg
. - Drag the Gold column to the Values section of the Columns Tool Panel and note that it is assigned the 'avg' function.
- The Silver column is configured to use a custom aggregation function as its default. Drag the Silver column to the Values section and note that it is assigned the function
mySum
. - Dragging the Bronze column will use
sum
as the default.
Note that unlike aggFunc
you can't pass a custom aggregation function directly to defaultAggFunc
, as demonstrated in the previous example, it must be registered first. See Registering Custom Functions for how to do this.
Restricting Aggregation Functions
By default, all functions are available to all value columns. To restrict the aggregation functions available on a value column, use the allowedAggFuncs
column property as shown below:
<ag-grid-vue
:columnDefs="columnDefs"
/* other grid options ... */>
</ag-grid-vue>
this.columnDefs = [
{
field: 'gold',
aggFunc: 'sum',
// restricts agg functions to be: `sum`, `min` and `max`
allowedAggFuncs: ['sum', 'min', 'max'],
}
];
The following example demonstrates restricting the aggregation functions. Note the following:
- The Gold column is configured with
allowedAggFuncs
set to['sum', 'min', 'max']
and only displays these functions in the drop-down list in the Values section column to the of the Columns Tool Panel. - The Silver column shows all available agg functions as it hasn't been restricted.
Aggregation API
After the grid is initialised aggregations can be applied / retrieved / removed via the api
with the following methods:
Get a list of the existing value columns. |
Add the given list of columns to the existing set of value columns. |
Remove the given list of columns from the existing set of value columns. |
Set the value columns to the provided list of columns. |
Sets the agg function for a column. aggFunc can be one of the built-in aggregations or a custom aggregation by name or direct function. |
When the grid initialises, any column definitions that have aggFunc
set will be automatically added as a value column.
Column Headers
When aggregating, the column headers will include the aggregation function for the column. For example the header 'Bank Balance'
will become 'sum(Bank Balance)'
if you have the sum aggregation active on the column. To turn this off and display simply 'Bank Balance'
then set the grid property suppressAggFuncInHeader
.
When true , column headers won't include the aggFunc name, e.g. 'sum(Bank Balance) ' will just be 'Bank Balance' . |
Empty Aggregation Calls
When providing either Custom Aggregation Functions or Custom Full Row Aggregation then you will see strange calls to these functions where empty lists are provided.
The empty aggregation calls happen in the following two scenarios:
- The grid has no data (usually the case when the gird is initially displayed before the application has set data). Aggregating at the root level will request an aggregation of an empty set.
- The grid has groups and a filter, such that groups are empty.
Recomputing Aggregates
If the data changes after the aggregation is done, you can tell the grid to recompute the aggregates through the API method refreshClientSideRowModel('aggregate')
.
Refresh the Client-Side Row Model, executing the grouping, filtering and sorting again.
Optionally provide the step you wish the refresh to apply from. Defaults to everything . |
Enabling Top Level Aggregations
When aggregations are present, the grid omits aggregating all the top level rows into one parent row as this total aggregation is not shown in the grid. Some applications may wish to use this value via the API, so the property alwaysAggregateAtRootLevel
can be enabled to force this value to always calculate. The grid will still selectively calculate the top level aggregation in scenarios where it is needed, eg if grandTotalRow
is enabled, or if the root level is being displayed for pivoting.
Next Up
Continue to the next section to learn about Tree Data.