group( )

Groups items together in an aggregation.

Description

The group() function refines a WixDataAggregate so that its items are grouped by the specified property or properties.

You can perform aggregations on the groups using the following functions:

To filter grouped results, use the having() function.

Note: Aggregations can only be used on collections you have created. They cannot be used on Wix App Collections.

Syntax

function group(propertyName: ...string): WixDataAggregate

group Parameters

NAME

TYPE

DESCRIPTION

propertyName

string

The property or properties to group on.

Returns

A WixDataAggregate object representing the refined aggregation.

Return Type:

WixDataAggregate

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Group items in an aggregation

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1let newAggregate = aggregate.group("state");

Group items by multiple fields in an aggregation

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1let newAggregate = aggregate.group("state", "year");

Group items in an aggregation and run the aggregation

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1import wixData from 'wix-data';
2
3// ...
4
5wixData.aggregate("PopulationData")
6  .group("state")
7  .max("population")
8  .run()
9  .then((results) => {
10    if (results.items.length > 0) {
11      let items = results.items;        // see below
12      let numItems = results.length;    // 3
13      let hasNext = results.hasNext();  // false
14    } else {
15      // handle case where no matching items found
16    }
17  })
18  .catch((error) => {
19    let errorMsg = error.message;
20    let code = error.code;
21  });
22
23/* Given the sample data above, items is:
24 * [
25 *   {"_id": "FL", "populationMax": 401000},
26 *   {"_id": "CA", "populationMax": 3796000},
27 *   {"_id": "NY", "populationMax": 8192000}
28 * ]
29 */

Group items in an aggregation and run the aggregation

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1import wixData from 'wix-data';
2
3// ...
4
5wixData.aggregate("PopulationData")
6  .group("state", "year")
7  .max("population")
8  .run()
9  .then((results) => {
10    if (results.items.length > 0) {
11      let items = results.items;        // see below
12      let numItems = results.length;    // 6
13      let hasNext = results.hasNext();  // false
14    } else {
15      // handle case where no matching items found
16    }
17  })
18  .catch((error) => {
19    let errorMsg = error.message;
20    let code = error.code;
21  });
22
23/* Given the sample data above, items is:
24 * [
25 *   {
26 *     "_id": {"state": "NY", "year": 2000},
27 *     "populationMax": 8015000,
28 *     "state": "NY",
29 *     "year": 2000
30 *   },
31 *   {
32 *     "_id": {"state": "FL", "year": 2000},
33 *     "populationMax": 362000,
34 *     "state": "FL",
35 *     "year": 2000
36 *   },
37 *   {
38 *     "_id": {"state": "NY", "year": 2010},
39 *     "populationMax": 8192000,
40 *     "state": "NY",
41 *     "year": 2010
42 *   },
43 *   {
44 *     "_id": {"state": "CA", "year": 2010},
45 *     "populationMax": 3796000,
46 *     "state": "CA",
47 *     "year": 2010
48 *   },
49 *   {
50 *     "_id": {"state": "CA", "year": 2000},
51 *     "populationMax": 3703000,
52 *     "state": "CA",
53 *     "year": 2000
54 *   },
55 *   {
56 *     "_id": {"state": "FL", "year": 2010},
57 *     "populationMax": 401000,
58 *     "state": "FL",
59 *     "year": 2010
60 *   }
61 * ]
62 */

Create an aggregation with filtering and grouping and run it

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1import wixData from 'wix-data';
2
3// ...
4
5const filter = wixData.filter().eq("year", 2010);
6const having = wixData.filter().gt("maxPopulation", 1000000);
7
8wixData.aggregate("PopulationData")
9  .filter(filter)
10  .group("state")
11  .max("population", "maxPopulation")
12  .having(having)
13  .descending("maxPopulation")
14  .skip(5)
15  .limit(3)
16  .run()
17  .then((results) => {
18    if (results.items.length > 0) {
19      let items = results.items;
20      let numItems = results.length;
21      let hasNext = results.hasNext();
22    } else {
23      // handle case where no matching items found
24    }
25  })
26  .catch((error) => {
27    let errorMsg = error.message;
28    let code = error.code;
29  });