指定軌跡屬性字段，根據(jù)固定值，過(guò)濾出符合條件的軌跡點(diǎn)，返回過(guò)濾后的屬性字段值（數(shù)組）。

語(yǔ)法

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);

參數(shù)

參數(shù)名稱 描述
traj 軌跡對(duì)象。
attr_field_name 指定的屬性名稱。
operator 過(guò)濾符，'='，'!='，'>'，'<'，'>='，'<='，'[]'，'(]'，'[)'，'()'。
value、value1 屬性固定值下限。
value2 屬性固定值上限。

描述

只支持類型為float的屬性字段。

示例

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]}}}'));


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)