QGIS/resources/function_help/json/geometry_overlay_equals

{
  "name": "geometry_overlay_equals",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Performs a spatial join of type EQUALS. This returns an array of results of an expression evaluated on features from a different layer that EQUALS the current feature, or, if no expression if provided, simply returns whether at least one feature from the other layer EQUALS the current feature.",
  "arguments": [
    {
      "arg": "layer",
      "description": "the other layer"
    },
    {
      "arg": "expression",
      "description": "an optional expression to evaluate on the features from the other layer (if not set, the function will just return a boolean indicating whether there is at least one match)",
      "optional": true
    },
    {
      "arg": "filter",
      "description": "an optional expression to filter the matching features (if not set, all features will be returned)",
      "optional": true
    },
    {
      "arg": "limit",
      "description": "an optional integer to limit the number of matching features (if not set, all features will be returned)",
      "optional": true
    },
    {
      "arg": "cache",
      "description": "set this to true to build a local spatial index (most of the time, this is unwanted, unless you are working with a particularly slow data provider)",
      "optional": true,
      "default": false
    }
  ],
  "examples": [
    {
      "expression": "geometry_overlay_equals('regions')",
      "returns": "True"
    },
    {
      "expression": "geometry_overlay_equals('regions', name)",
      "returns": "['South Africa', 'Africa', 'World']"
    },
    {
      "expression": "geometry_overlay_equals('regions', name, name != 'World')",
      "returns": "['South Africa', 'Africa']"
    },
    {
      "expression": "geometry_overlay_equals('regions', name, limit:=1)",
      "returns": "['South Africa']"
    }
  ]
}