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

Filters trajectory points by a float attribute field and returns the matching values as an array.

Syntax

float8[] ST_attrFloatFilter(trajectory traj, cstring attr_field_name, cstring operator, float8 value);
float8[] ST_attrFloatFilter(trajectory traj, cstring attr_field_name, cstring operator, float8 value1, float8 value2);

Parameters

Parameter	Description
`traj`	The trajectory object.
`attr_field_name`	The name of the attribute field to filter on.
`operator`	The comparison operator. Single-value operators: `'='`, `'!='`, `'>'`, `'<'`, `'>='`, `'<='`. Range operators: `'[]'`, `'(]'`, `'[)'`, `'()'`.
`value` / `value1`	The comparison value (single-value form), or the lower bound of the range (range form).
`value2`	The upper bound of the range. Used only in the range form.

Returns

float8[] — An array of attribute field values from the trajectory points that match the filter condition.

Usage notes

This function supports only float-type attribute fields.

Examples

Create a trajectory table and insert a sample trajectory with a heading attribute field (float type):

create table traj(id integer, traj trajectory);
insert into traj values(2,ST_makeTrajectory('STPOINT'::leaftype, 'LINESTRING(-179.48077 51.72814,-179.46731 51.74634,-179.46502 51.74934,-179.46183 51.75378,-179.45943 51.75736,-179.45560 51.76273,-179.44845 51.77186,-179.43419 51.78977,-179.41259 51.81643,-179.41001 51.81941,-179.40751 51.82223,-179.40497 51.82505,-179.40242 51.82796,-179.39981 51.83095,-179.39734 51.83398,-179.39499 51.83709)'::geometry, ARRAY['2017-01-15 09:06:39'::timestamp,'2017-01-15 09:14:48','2017-01-15 09:13:39','2017-01-15 09:16:28','2017-01-15 09:19:48','2017-01-15 09:17:48','2017-01-15 09:23:19','2017-01-15 09:34:40','2017-01-15 09:30:28','2017-01-15 09:36:59','2017-01-15 09:38:09','2017-01-15 09:39:18','2017-01-15 09:40:40','2017-01-15 09:47:38','2017-01-15 21:18:30','2017-01-15 09:48:49'], '{"leafcount": 16, "attributes": {"heading": {"type": "float", "length": 8, "nullable": false,"value":[23.0,23.0,23.0,23.0,21.0,21.0,72.0,72.0,72.0,72.0,73.0,74.0,73.0,73.0,73.0,73.0]}}}'));

Return all heading values greater than 23.0:

select st_attrFloatFilter(traj, 'heading', '>', 23.0) from traj where id = 2;
--        st_attrfloatfilter
-- ---------------------------------
--  {72,72,72,72,73,74,73,73,73,73}
-- (1 row)