Tutorial: Query a feature layer (SQL)

Import modules and login

1. Import the arcgis.gis module.

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from arcgis.gis import GIS

1. Create an anonymous connection to ArcGIS Online to access public data. Since this dataset is public you do not need credentials to access it. If it were a private dataset, you would be required to log in
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   from arcgis.gis import GIS
   
   portal = GIS()
   
   

Access the data

1. Use the ContentManager class to access the dataset by Item ID.

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   portal = GIS()
   
   parcel_layer_item = portal.content.get("a6fdf2ee0e454393a53ba32b9838b303")
   
   parcel_layer = parcel_layer_item.layers[0]
   
   

Run the query

1. Create a string variable containing the SQL statement. This will query only the features of this feature layer thats UseType attribute is set as Residential. Pass this in the where parmeter to the query() method of the FeatureLayer object. The as_df parameter is set to False so that the results will be returned as FeatureSet. The return_all_records and result_record_cout parameters are used to only return the first 100 records satisifying the query. Set the out_fields as an array of field names to return in the results.
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   parcel_layer_item = portal.content.get("a6fdf2ee0e454393a53ba32b9838b303")
   
   parcel_layer = parcel_layer_item.layers[0]
   
   where_clause = "UseType = 'Residential'"
   
   results = parcel_layer.query(
     where = where_clause,
     as_df = False,
     return_all_records = False,
     result_record_count = 100,
     out_fields = "APN, UseType"
   )
   
   

Display the results

1. Use the map method to create a map widget. Use the add_layer() method to add the results featureset to the map and the zoom_to_layer() method to set the maps extent so the query results are visibile.s

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   where_clause = "UseType = 'Residential'"
   
   results = parcel_layer.query(
     where = where_clause,
     as_df = False,
     return_all_records = False,
     result_record_count = 100,
     out_fields = "APN, UseType"
   )
   
   map = portal.map()
   map
   
   map.add_layer(results)
   map.zoom_to_layer(results)
   
   

2. Optional: Export map widget state as a static .html file.

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   map = portal.map()
   map
   
   map.add_layer(results)
   map.zoom_to_layer(results)
   
   import os
   file_path = os.path.join(os.getcwd(), "home", "query-a-feature-layer-sql.html")
   
   map.export_to_html(file_path, title="Query a feature layer (SQL)")