ST_trajAttrsAsTimestamp-AnalyticDB(AnalyticDB)-阿里云帮助中心

Returns all values of a timestamp-type attribute field from a trajectory object as an array.

Syntax

timestamp[] ST_trajAttrsAsTimestamp(trajectory traj, text attr_name)

Parameter	Description
`traj`	The trajectory object.
`attr_name`	The name of the attribute field.

Example

The following example constructs a trajectory with a timestamp-type attribute field named tngel2, then retrieves all its values.

WITH traj AS (
  SELECT '{
    "trajectory": {
      "version": 1,
      "type": "STPOINT",
      "leafcount": 2,
      "start_time": "2010-01-01 11:30:00",
      "end_time": "2010-01-01 12:30:00",
      "spatial": "SRID=4326;LINESTRING(1 1,3 5)",
      "timeline": ["2010-01-01 11:30:00", "2010-01-01 12:30:00"],
      "attributes": {
        "leafcount": 2,
        "velocity": {"type": "integer", "length": 4, "nullable": true, "value": [1, null]},
        "speed":    {"type": "float",   "length": 8, "nullable": true, "value": [null, 1.0]},
        "angle":    {"type": "string",  "length": 64,"nullable": true, "value": ["test", null]},
        "tngel2":   {"type": "timestamp","length": 8,"nullable": true, "value": ["2010-01-01 12:30:00", null]},
        "bearing":  {"type": "bool",    "length": 1, "nullable": true, "value": [null, true]}
      }
    }
  }'::trajectory a
)
SELECT ST_trajAttrsAsTimestamp(a, 'tngel2') FROM traj;
-- {"2010-01-01 12:30:00",NULL}