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

Returns the nearest distance between two trajectory objects within a specified time range.

Syntax

float8 ST_nearestApproachDistance(trajectory traj, trajectory traj2);
float8 ST_nearestApproachDistance(trajectory traj, trajectory traj2, tsrange range);
float8 ST_nearestApproachDistance(trajectory traj, trajectory traj2, timestamp t1, timestamp t2);

Parameters

Parameter	Description
`traj1`	The first trajectory object.
`traj2`	The second trajectory object.
`range`	The time range, specified as a `tsrange` value.
`t1`	The start of the time range.
`t2`	The end of the time range.

Return value

Returns a float8 value representing the nearest distance between the two trajectory objects.

Examples

The following example calculates the nearest approach distance between the trajectories of objects with IDs 1 and 2 between 13:00 and 14:00 on January 1, 2010.

SELECT ST_nearestApproachDistance(
  (SELECT traj FROM traj_table WHERE id = 1),
  (SELECT traj FROM traj_table WHERE id = 2),
  '2010-1-1 13:00:00',
  '2010-1-1 14:00:00'
);