WhereClause | References | ArcGIS Maps SDK for JavaScript

import WhereClause from "@arcgis/core/core/sql/WhereClause.js";

const WhereClause = await $arcgis.import("@arcgis/core/core/sql/WhereClause.js");

Since: ArcGIS Maps SDK for JavaScript 4.14

The WhereClause is used to extract the features that meet a specified condition by parsing the provided results in to a value. The parseWhereClause() method returns a Promise that resolves to an instance of this module.

See also

Standardized SQL functions in ArcGIS Online

Properties

Property	Type	Class
fieldNames readonly	string[]
isStandardized readonly	boolean
parseTree readonly	SQLNode

fieldNames

readonly Property

Type: string[]

An array of the field names used in the where clause. It can be used to get the appropriate fields when querying layers.

Example

// parse layer's definition expression into where clause object
sql.parseWhereClause(layer.definitionExpression, layer.fieldsIndex)
.then(function(clause){
  layer.queryFeatures({
    where: "1=1",
    // where clause object returns layer fields
    // use these fields to query features from the layer
    outFields: clause.fieldsNames
  }).then(function(results) {
   // process query results
  });
});

isStandardized

readonly Property

Type: boolean

Returns true if the parsed where clause meets the requirements of standardized sql.

parseTree

readonly Property

Type: SQLNode

Since: ArcGIS Maps SDK for JavaScript 4.24

A parse tree is a data structure for representing a parsed sql statement. Parsing a statement requires the grammar of the language that the statement was written.

See also

Methods

Method	Signature	Class
calculateValue	calculateValue(feature: SimpleAttributes): any
testFeature	testFeature(feature: SimpleAttributes): boolean

calculateValue

Method

Signature: calculateValue (feature: SimpleAttributes): any

Executes the where clause against a feature to generate a value. It is used when the WhereClause is being used as a simple expression. For example, you can use the expression to gather values for statistics.

Parameters

Parameter	Type	Description	Required
feature	SimpleAttributes	The feature to check against the where clause.

Returns: any
Returns a value after check feature against the provided where clause. Returns null if the provided value is unknown.

Example

// calculate the grand total sales price of all features
featureLayer.queryFeatures().then(function(results){
  let total;
  const expression = "totalSales * totalPrice";
  sql.parseWhereClause(expression, layer.fieldsIndex)
  .then(function(whereClause){
    // check if the where clause meets requirements of standardized sql
    if (whereClause.isStandardized){
      features.forEach(function(feature){
        total += whereClause.calculateValue(feature)
      });
      console.log(total); // prints the total sales price of all features
    }
  });
});

testFeature

Method

Signature: testFeature (feature: SimpleAttributes): boolean

Tests the attributes of a feature against the whereClause, and returns true if the test passes, false otherwise.

Parameters

Parameter	Type	Description	Required
feature	SimpleAttributes	The feature to test against the `whereClause`.

Returns: boolean
Returns true if the test passes, false otherwise.

Example

sql.parseWhereClause("POPULATION > 100000", layer.fieldsIndex)
.then(function(clause){
  let testResult = clause.testFeature(new Graphic({
    attributes: {
      POPULATION: 300000
   }
 });
 console.log(testResult); // prints true
});