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.

Notes:
Aggregations can only be used on collections you have created. They cannot be used on Wix App Collections.
You can only call the group() function once per aggregate query.

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  });