为什么在使用嵌套查询时无法引用用户定义的类型字段？

So I have the following user defined type in my oracle database:

所以我的oracle数据库中有以下用户定义的类型:

CREATE OR REPLACE TYPE METRIC_IMPERIAL_DISTANCE AS OBJECT
(
  METERS_FEET INTEGER,
  CENTIMETERS_INCHES INTEGER,
  FRACTION NUMBER
)

I can do the following:

我可以做以下事情:

SELECT t_id, get_distance_breakdown (h.height, h.unit_of_measure_id) height_breakdown
        FROM   heights h

and even

SELECT t_id, get_distance_breakdown (h.height, h.unit_of_measure_id).meters_feet height_meters_feet
        FROM   heights h

but the following fails with a ORA-00904: "HEIGHT_BREAKDOWN"."METERS_FEET": invalid identifier error:

但是下面的ORA-00904失败了:“HEIGHT_BREAKDOWN”。“METERS_FEET”:标识符无效错误:

SELECT t_id, height_breakdown.meters_feet
FROM   (SELECT t_id, get_distance_breakdown (h.height, h.unit_of_measure_id) height_breakdown
        FROM   heights h);

What gives? If there isn't some simple and obvious work-around for this then that decimates much of what would be useful about oracle's user defined types. I feel like I must be missing something.

是什么赋予了?如果没有一些简单而明显的解决办法,那么就会大量抽取oracle用户定义类型的大部分内容。我觉得我必须遗漏一些东西。

1 个解决方案

#1

I believe Oracle needs an alias for the in-line view:

我相信Oracle需要内联视图的别名:

SELECT v.t_id, v.height_breakdown.meters_feet
FROM   (SELECT t_id, get_distance_breakdown (h.height, h.unit_of_measure_id) height_breakdown
        FROM   heights h) v;