Filter a feature layer with SQL

Learn how to use a SQL query to limit features displayed in a feature layer.

A hosted feature layer can contain a large number of features. To display a subset of the features, you can filter features on the server-side with a definition expression. Definition expressions are different than feature layer queries: they only support a SQL where clause without a geometry (spatial) parameter, and are only used to filter features at the time they are displayed in a map or scene. They cannot be used to get features like a feature layer query.

In this tutorial, you will apply a server-side SQL query with a definitionExpression to filter the LA County Parcels feature layer .

Prerequisites

Steps

Create a new pen

To get started, either complete the Display a map tutorial or .

Get an access token

You need an access token with the correct privileges to access the location services used in this tutorial.

Go to the Create an API key tutorial and create an API key with the following privilege(s):
- Privileges
  - Location services > Basemaps

In CodePen, set esriConfig.apiKey to your access token.

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  var esriConfig = {
    apiKey: "YOUR_ACCESS_TOKEN",
  };

To learn about other ways to get an access token, go to Types of authentication.

Create a selector

Use a Calcite Select component to provide a list of SQL queries for the LA County Parcels feature layer.

Add a Calcite Select component within the arcgis-map component in the top-right slot. This component has child Option components, each with a different SQL query.

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      <calcite-select id="sqlSelect" slot="top-right">
        <calcite-option value="1=0" label="Choose a SQL where clause..."></calcite-option>
        <calcite-option
          value="Roll_LandValue < 200000"
          label="Roll_LandValue < 200000"></calcite-option>
        <calcite-option value="TaxRateArea = 10853" label="TaxRateArea = 10853"></calcite-option>
        <calcite-option value="Bedrooms5 > 0" label="Bedrooms5 > 0"></calcite-option>
        <calcite-option
          value="UseType = 'Residential'"
          label="UseType = 'Residential'"></calcite-option>
        <calcite-option
          value="Roll_RealEstateExemp > 0"
          label="Roll_RealEstateExemp > 0"></calcite-option>
      </calcite-select>
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Verify that the select component is created.

Add modules and a map component event listener

Add a <script> tag in the <body> following the <arcgis-map> component. Use $arcgis.import() to add the FeatureLayer module.

The ArcGIS Maps SDK for JavaScript is available via CDN and npm, but this tutorial is based on CDN. The $arcgis.import global function accepts a module path or array of module paths, and returns a promise that resolves with the requested modules. This function can only be used when working with the CDN; otherwise, use the standard import syntax. To learn more about the SDK's different modules, visit the References page.

Use the document.querySelector() method to access the map and select components.

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  <body>

    <arcgis-map basemap="arcgis/topographic" center="-118.805, 34.020" zoom="13">

      <arcgis-zoom slot="top-left"></arcgis-zoom>

      <calcite-select id="sqlSelect" slot="top-right">
        <calcite-option value="1=0" label="Choose a SQL where clause..."></calcite-option>
        <calcite-option
          value="Roll_LandValue < 200000"
          label="Roll_LandValue < 200000"></calcite-option>
        <calcite-option value="TaxRateArea = 10853" label="TaxRateArea = 10853"></calcite-option>
        <calcite-option value="Bedrooms5 > 0" label="Bedrooms5 > 0"></calcite-option>
        <calcite-option
          value="UseType = 'Residential'"
          label="UseType = 'Residential'"></calcite-option>
        <calcite-option
          value="Roll_RealEstateExemp > 0"
          label="Roll_RealEstateExemp > 0"></calcite-option>
      </calcite-select>

    </arcgis-map>

    <script type="module">

      const FeatureLayer = await $arcgis.import("@arcgis/core/layers/FeatureLayer.js");

      const viewElement = document.querySelector("arcgis-map");
      const selectFilter = document.querySelector("#sqlSelect");

    </script>

  </body>
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Wait for the Map component to be ready with the viewOnReady method.

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    <script type="module">

      const FeatureLayer = await $arcgis.import("@arcgis/core/layers/FeatureLayer.js");

      const viewElement = document.querySelector("arcgis-map");
      const selectFilter = document.querySelector("#sqlSelect");

      await viewElement.viewOnReady();

    </script>
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Create a feature layer to filter

Use the FeatureLayer class to access the LA County Parcels feature layer. Since you are performing a server-side query, the feature layer does not need to be added to the map. However, to view the results of the query, the feature layer will be added to the map.

Create a featureLayer and set the url property to access the feature layer in the feature service. Set the outFields property to return all attributes on the client and the popupTemplate to display the parcel description and land value. Set the definitionExpression to 1=0 so no features are displayed when the layer is loaded. Add featureLayer to the map.

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      await viewElement.viewOnReady();

      const featureLayer = new FeatureLayer({
        url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/LA_County_Parcels/FeatureServer/0",
        outFields: ["*"],
        popupTemplate: {
          title: "{UseType}",
          content: "Description: {UseDescription}. Land value: {Roll_LandValue}",
        },
        definitionExpression: "1=0",
      });
      viewElement.map.add(featureLayer);

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Apply the SQL expression

The definitionExpression is the SQL where clause. Use the expression to apply a filter and limit features displayed in the map.

Create a setFeatureLayerFilter function with an expression parameter. Set the definitionExpression to filter the feature layer with the expression.

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      await viewElement.viewOnReady();

      const featureLayer = new FeatureLayer({
        url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/LA_County_Parcels/FeatureServer/0",
        outFields: ["*"],
        popupTemplate: {
          title: "{UseType}",
          content: "Description: {UseDescription}. Land value: {Roll_LandValue}",
        },
        definitionExpression: "1=0",
      });
      viewElement.map.add(featureLayer);

      // Server-side filter
      function setFeatureLayerFilter(expression) {
        featureLayer.definitionExpression = expression;
      }

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Add an event listener to call the setFeatureLayerFilter function when a SQL where clause is chosen from the selector.

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      await viewElement.viewOnReady();

      const featureLayer = new FeatureLayer({
        url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/LA_County_Parcels/FeatureServer/0",
        outFields: ["*"],
        popupTemplate: {
          title: "{UseType}",
          content: "Description: {UseDescription}. Land value: {Roll_LandValue}",
        },
        definitionExpression: "1=0",
      });
      viewElement.map.add(featureLayer);

      // Server-side filter
      function setFeatureLayerFilter(expression) {
        featureLayer.definitionExpression = expression;
      }

      // Event listener
      selectFilter.addEventListener("calciteSelectChange", (event) => {
        setFeatureLayerFilter(event.target.value);
      });
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Run the app

In CodePen, run your code to display the map.

When the map displays, you should be able to choose a SQL query from the selector that applies a definition expression to the visible extent of the map. Only the features that match are added to the feature layer and displayed in the view.

What's next?

Learn how to use additional SDK features and ArcGIS services in these tutorials: