POSTGRES - 将相同的列与不同的文本组合在一行中

Question

我有三个要合并的表。我有一个表医生，病人和手术。医生代表所有医生。 Patient 代表患者，操作持有来自患者和医生的主要密钥。 我如何编写一个查询来显示我的 ChiefDoctor 和 assistantDoctor 和 Patient？到目前为止我达到了什么？

显示首席医生或助理医生的名字和姓氏。我如何写来显示一张同时包含首席和助理的表格？

select a.vorname|| ' ' || a.nachname AS leitenderArzt, p.firstname || ' ' || p.lastname AS patient
from angestellter a inner join operation o on a.id = o.leitenderarzt
inner join patient p on o.patientident=p.ident

| id | firstname       | lastname      | patient      |
| 1  | ImA             | ChiefDoctor1  | p.firstname  |
| 3  | ImA             | ChiefDoctor3  | p.firstname  |

我的数据库的底层结构与表示。

CREATE TABLE doctor
(
  id serial NOT NULL,  
  firstname character varying(255) NOT NULL,
  lastname character varying(255) NOT NULL,  
  CONSTRAINT angestellter_pkey PRIMARY KEY (id),
}

 Table doctor
 |id | firstname | lastname        |
 | 1 | ImA       | ChiefDoctor1    |
 | 2 | ImA       | AssistantDoctor |
 | 3 | ImA       | ChiefDoctor2    |

CREATE TABLE patient
(
  ident serial NOT NULL,  
  firstname character varying(255) NOT NULL,
  lastname character varying(255) NOT NULL,
  CONSTRAINT patient_pkey PRIMARY KEY (ident),
}

Table patient
| ident | firstname | lastname |
| 1     | Operated  | ME       |

CREATE TABLE operation
(
  id serial NOT NULL,
  chiefDoctor integer NOT NULL,
  AssistantDoctor integer NOT NULL,
  patientident integer NOT NULL,
  CONSTRAINT operation_pkey PRIMARY KEY (id),
  CONSTRAINT fkoperation539608 FOREIGN KEY (patientident)
      REFERENCES patient (ident) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT fkoperation745809 FOREIGN KEY (assistantDoctor)
      REFERENCES angestellter (id) MATCH SIMPLE
      ON UPDATE NO ACTION ON DELETE NO ACTION,
  CONSTRAINT fkoperation949671 FOREIGN KEY (chiefDoctor)
      REFERENCES angestellter (id) MATCH SIMPLE
}

Table operation
| id | doctorID | doctorID | patientID |
| 1  |    1     |    2     |     1     |

我如何编写一个查询来显示谁操作了一个全名的病人？它应该是这样的。

| id | chiefdoctor       | assistantdoctor      | patient      |
|----| ImA + ChiefDoctor |ImA + AssistantDoctor | Operated + ME|

Answer 1

第一个也是最直观的方法是加入两次医生：

select o.id
     , d1.firstname || ' + ' || d1.lastname as chiefdoctor
     , d2.firstname || ' + ' || d2.lastname as assistantdoctor
     , p.firstname || ' + ' || p.lastname as patient
from operation o
join doctor d1
    on o.chiefDoctor = d1.id
join doctor d2
    on o.AssistantDoctor = d2.id
join patient p
    on o.patientident = p.ident

您可能希望修剪名称，如下所示：

trim(both from d1.firstname) || ' + ' || trim(both from d1.lastname)

但我觉得这不是你最关心的问题，所以为了缩短解决方案，我把它省略了