获得作为文本类型的轨迹属性数组。
语法
bool[] st_trajAttrsAsBool(trajectory traj, text attr_name);
参数
| 参数名称 | 描述 |
|---|---|
| traj | 轨迹对象。 |
| a?ttr_name | 属性名称。 |
示例
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]},"angel":{"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_trajAttrsAsBool(a, 'velocity') from traj;
st_trajattrsasbool
--------------------
{t,NULL}
(1 row)
