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

You need an ArcGIS Developer or ArcGIS Online account to access the dashboard and create an API key.

Steps

Create a new pen

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

Set the API key

To access ArcGIS services, you need an API key.

Go to your dashboard to get an API key.
In CodePen, set the apiKey to your key, so it can be used to access basemap layer and location services.

Use dark colors for code blocks
esriConfig.apiKey = "YOUR_API_KEY";
const map = new Map({
  basemap: "arcgis/topographic" // basemap styles service
});

Add modules

In the require statement, add the FeatureLayer module.

The ArcGIS Maps SDK for JavaScript is available as AMD modules and ES modules, but this tutorial is based on AMD. The AMD require function uses references to determine which modules will be loaded – for example, you can specify "esri/Map" for loading the Map module. After the modules are loaded, they are passed as parameters (e.g. Map) to the callback function where they can be used in your application. It is important to keep the module references and callback parameters in the same order. For more information on the different types of modules, visit the Introduction to Tooling guide topic.

Expand
Use dark colors for code blocks
  <script>
    require([
      "esri/config",
      "esri/Map",
      "esri/views/MapView",

      "esri/layers/FeatureLayer"

    ], function (esriConfig, Map, MapView, FeatureLayer) {
Expand

Create a selector

Use an HTML select element to provide a list of SQL queries for the LA County Parcels feature layer.

Create a sqlExpressions array of SQL queries.

Expand
Use dark colors for code blocks
      const view = new MapView({
        container: "viewDiv",
        map: map,
        center: [-118.80543, 34.02700], // Longitude, latitude
        zoom: 12
      });

      // Create a UI with the filter expressions
      const sqlExpressions = ["Choose a SQL where clause...", "Roll_LandValue < 200000", "TaxRateArea = 10853", "Bedrooms5 > 0", "UseType = 'Residential'", "Roll_RealEstateExemp > 0"];
Expand

Create a parent selectFilter element and add option elements for each SQL query. Add some css styles to the elements.

Expand
Use dark colors for code blocks
      // Create a UI with the filter expressions
      const sqlExpressions = ["Choose a SQL where clause...", "Roll_LandValue < 200000", "TaxRateArea = 10853", "Bedrooms5 > 0", "UseType = 'Residential'", "Roll_RealEstateExemp > 0"];

      // UI
      const selectFilter = document.createElement("select");
      selectFilter.setAttribute("class", "esri-widget esri-select");
      selectFilter.setAttribute("style", "width: 275px; font-family: Avenir Next; font-size: 1em;");

      sqlExpressions.forEach(function (sql) {
        let option = document.createElement("option");
        option.value = sql;
        option.innerHTML = sql;
        selectFilter.appendChild(option);
      });

Expand

Add selectFilter to the top-right corner of the view.

Expand
Use dark colors for code blocks
      sqlExpressions.forEach(function (sql) {
        let option = document.createElement("option");
        option.value = sql;
        option.innerHTML = sql;
        selectFilter.appendChild(option);
      });

      view.ui.add(selectFilter, "top-right");
Expand

Verify that the select element is created.

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.

Expand
Use dark colors for code blocks
      view.ui.add(selectFilter, "top-right");

      // Add a feature layer to map with all features visible on client (no filter)
      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"
      });
      map.add(featureLayer);

Expand

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.

Expand
Use dark colors for code blocks
      view.ui.add(selectFilter, "top-right");

      // Add a feature layer to map with all features visible on client (no filter)
      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"
      });
      map.add(featureLayer);

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

Expand

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

Expand
Use dark colors for code blocks
      // Server-side filter
      function setFeatureLayerFilter(expression) {
        featureLayer.definitionExpression = expression;
      }

      // Event listener
      selectFilter.addEventListener('change', function (event) {
        setFeatureLayerFilter(event.target.value);
      });
Expand

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 API features and ArcGIS services in these tutorials: