QGIS/resources/function_help/json/z_min

{
  "name": "z_min",
  "type": "function",
  "groups": ["GeometryGroup"],
  "description": "Returns the minimum z coordinate of a geometry, or NULL if the geometry has no z value.",
  "arguments": [ {"arg":"geometry","description":"a geometry with z coordinate"}],
  "examples": [ { "expression":"z_min( geom_from_wkt( 'POINT ( 0 0 1 )' ) )", "returns":"1"},
                { "expression":"z_min( geom_from_wkt( 'MULTIPOINT ( 0 0 1 , 1 1 3 )' ) )", "returns":"1"},
                { "expression":"z_min( make_line( make_point( 0,0,0 ), make_point( -1,-1,-2 ) ) )", "returns":"-2"},
                { "expression":"z_min( geom_from_wkt( 'LINESTRING( 0 0 0, 1 0 2, 1 1 -1 )' ) )", "returns":"-1"},
                { "expression":"z_min( geom_from_wkt( 'POINT ( 0 0 )' ) )", "returns":"NULL"}
  ]
}