query

require([
  "esri/rest/query"
], function(query) {
  // url to the layer of interest to query
  let queryUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/3";

  query.executeForCount(queryUrl, {  // autocasts as new Query()
     where: "POP07_SQMI > 100"
  }).then(function(count){
    console.log(count, " features matched the input query");
  }, function(error){
       console.log(error); // will print error in console if unsupported layers are used
     });
});

require([
  "esri/rest/query"
], function(query) {
  // url to the layer of interest to query
  let queryUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/3";

  query.executeForIds(queryUrl, {  // autocasts as new Query()
     where: "SUB_REGION = 'Pacific'"
  }).then(function(results){
    console.log(results);  // an array of object IDs
  });
  ...
});

// set the query to return a count
// of features that has most sales grouped by regions.
// top query will run against all features available in the service
const query = new TopFeaturesQuery({
  topFilter: new TopFilter({
    topCount: 1,
    groupByFields: ["Region"],
    orderByFields: ["Sales DESC"]
  })
});
executeForTopCount(url, query)
  .then(function(response){
     // returns the number of the features that have the most sales by region.
   });

// Get the count and extent of the three highest magnitude earthquakes
// in each region.
const query = new TopFeaturesQuery({
  where: "mag >= 6",
  geometry: studyExtent,
  topFilter: new TopFilter({
    topCount: 3,
    groupByFields: ["region"],
    orderByFields: ["mag DESC"]
  })
});
executeForTopExtents(url, query)
  .then(function(response){
     // returns the count and extent of top three earthquakes within each region
   });

// Get the objectIds top three earthquakes
// grouped by regions and ordered by their magnitude levels
// top query will only run against earthquakes that have mag >=6.
const query = new TopFeaturesQuery({
  where: "mag >= 6",
  topFilter: new TopFilter({
    topCount: 3,
    groupByFields: ["region"],
    orderByFields: ["mag DESC"]
  })
});
executeTopFeaturesQuery(url, query)
  .then(function(response){
     // returns an array of object ids of top three earthquakes within each region
   });

require([
  "esri/rest/query", "esri/rest/support/Query"
], function(query, Query) {
  // url to the layer of interest to query
  let queryUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/3";

  // create the Query object
  let queryObject = new Query();
  queryObject.where = "STATE_NAME = 'Washington'";
  queryObject.outSpatialReference = { wkid:4269 };
  queryObject.returnGeometry = true;
  queryObject.outFields = [ "HOUSEHOLDS" ];

  // call the executeQueryJSON() method
  query.executeQueryJSON(queryUrl, queryObject).then(function(results){
    // results.graphics contains the graphics returned from query
  });
  ...
});

require([
  "esri/rest/query", "esri/rest/support/Query"
], function(query, Query) {
  // url to the layer of interest to query
  let queryUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/3";

  // create the Query object
  let queryObject = new Query();
  queryObject.where = "STATE_NAME = 'Washington'";
  queryObject.outSpatialReference = { wkid:4269 };
  queryObject.returnGeometry = true;
  queryObject.outFields = [ "HOUSEHOLDS" ];

  // call the executeQueryPBF() method
  query.executeQueryPBF(queryUrl, queryObject).then(function(results){
    // results.graphics contains the graphics returned from query
  });
  ...
});

require([
  "esri/rest/query", "esri/rest/support/RelationshipQuery"
], function(query, RelationshipQuery) {
  // url to the layer of interest to query
  let queryUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/0";

  // specify relationship query parameter
  const queryRelationship = new RelationshipQuery({
     outFields: ["*"],
     relationshipId: relationshipId,
     objectIds: [11, 22]
  });

  // query related features that meet the query parameters
  query.executeRelationshipQuery(queryUrl, queryRelationship).then((results) => {
     console.log("query results", results);
  })
  .catch((error) => {
     console.log("query error", error);
  });

// Query the most visited national parks in each state
// and order them by the most visited
// query will run against all features available in the service
const query = new TopFeaturesQuery({
  outFields: ["State, TOTAL, Park"],
  topFilter: new TopFilter({
    topCount: 1,
    groupByFields: ["State"],
    orderByFields: ["TOTAL DESC"]
  })
});
executeTopFeaturesQuery(url, query)
  .then(function(response){
     // returns a feature set with features containing the most visited
     // national park in each state ordered by the number of visits.
     // The following attributes are returned as well: State, TOTAL, Park
   });