ST_eventTypes-PolarDB(PolarDB)-阿里云帮助中心

Returns the type IDs of all events in a trajectory object as an integer array.

Syntax

integer[] ST_eventTypes(trajectory traj)

Parameters

Parameter	Description
`traj`	The trajectory object to query.

Example

The following example retrieves the event type IDs from a trajectory with two events of type 1 and type 2.

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]}},"events":[{"1":"Fri Jan 01 14:30:00 2010"},{"2":"Fri Jan 01 14:30:00 2010"}]}}'::trajectory a)
SELECT ST_eventTypes(a) FROM traj;
-- {1,2}