嵌套 Case 语句类型错误 (postgres)

我创建的一些 postgres 代码给了我一个错误：

ERROR:  CASE types character varying and numeric cannot be matched

CODE:

CREATE TABLE current_condition_joined AS SELECT
a.id, a.geom, a.condition_join_1, a.condition_join_2, a.condition_join_3,
(CASE WHEN b.condition = 'ERROR' THEN (CASE WHEN c.condition2 = 'ERROR' THEN d.condition3
                                       ELSE c.condition2
                                       END)
 ELSE b.condition
 END) current_condition,
(CASE WHEN b.condition= 'ERROR' THEN (CASE WHEN c.condition2 = 'ERROR' THEN d.ecosite3
                                      ELSE c.ecosite2
                                      END)
 ELSE b.ecosite
 END) current_ecosite,
(CASE WHEN b.condition = 'ERROR' THEN (CASE WHEN c.condition2 = 'ERROR' THEN d.ecophase3
                                       ELSE c.ecophase2
                                       END)
 ELSE b.ecophase
 END) current_ecophase,
(CASE WHEN b.condition = 'ERROR' THEN (CASE WHEN c.condition2 = 'ERROR' THEN d.consite3
                                       ELSE c.consite2
                                       END)
 ELSE b.consite
 END) current_consite,
(CASE WHEN b.condition = 'ERROR' THEN (CASE WHEN c.condition2 = 'ERROR' THEN d.conphase3
                                       ELSE c.conphase2
                                       END)
 ELSE b.conphase
 END) current_conphase
 FROM current_condition a, boreal_mixedwood_labeled b, boreal_mixedwood_labeled c, boreal_mixedwood_labeled d
 WHERE a.label = b.label_join_1
   and a.label2 = c.label_join_2
   and a.label3 = d.label_join_3;

b、c、d Ecosite 和 Phase 均为数字类型。唯一的条件是 varchar。

在第二列和第三列创建中是发生问题的地方。我假设我收到错误，因为在案例的第一部分中它引用了 varchar，但第二个案例的结果是数字。我想使用条件“错误”来选择要使用的数值。

我是 postgres (9.4.5) 的新手，但对 sql 相当精通。我正在 Windows 机器上的 pgAdmin（v.1.18.1）中工作。

我已经查看了问题的其他实例，但它们没有考虑嵌套语句。我的案例出了什么问题？ https://stackoverflow.com/questions/9707863/whats-wrong-with-my-case

从 PGAdmin 中的 SQL 窗格创建表 current_condition 的代码：

CREATE TABLE current_condition (
  geom geometry,
  condition_join_1 text,
  condition_join_2 text,
  condition_join_3 text,
  id serial NOT NULL,
  CONSTRAINT current_condition_pkey PRIMARY KEY (id)
);

CREATE INDEX idx_current_condition_geom
  ON current_condition USING gist (geom);

boreal_mixedwood_labeled 表的代码：

CREATE TABLE boreal_mixedwood_labeled
(
  objectid serial NOT NULL,
  label character varying(255),
  label2 character varying(255),
  label3 character varying(255),
  condition character varying(255),
  ecophase numeric(15,6),
  ecosite numeric(15,6),
  conphase character varying(255),
  consite character varying(255),
  condition2 character varying(255),
  ecophase2 numeric(15,6),
  ecosite2 numeric(15,6),
  conphase2 character varying(255),
  consite2 character varying(255),
  condition3 character varying(255),
  ecophase3 numeric(15,6),
  ecosite3 numeric(15,6),
  conphase3 character varying(255),
  consite3 character varying(255),
  CONSTRAINT boreal_mixedwood_labeled_pkey PRIMARY KEY (objectid)

埃尔文的回答是正确的。虽然列中的值是数字，但由于某种原因，表将它们作为字符。一定是从我的导入中自动发生的。

尝试消除嵌套case。也许由于某种原因它会对编译器产生影响：

CASE
    WHEN b.condition = 'ERROR' AND c.condition2 = 'ERROR' THEN d.condition3
    WHEN b.condition = 'ERROR' THEN c.condition2
    ELSE c.condition
END as current_condition,
...