sql语句错误：“列..不存在”

Question

我正在从 postgres 控制台尝试这个命令：

select sim.id as idsim, 
       num.id as idnum 
from main_sim sim 
  left join main_number num on (FK_Numbers_id=num.id);

我收到了这样的回复：

错误：列“fk_numbers_id”不存在 LINE 1: ...m from main_sim sim left join main_number num on (FK_Numbers...

但如果我只是检查我的表：

dbMobile=# \d main_sim

 id              | integer               | not null default

 Iccid           | character varying(19) | not null

...

 FK_Device_id    | integer               | 

 FK_Numbers_id   | integer               | 

Indexes:
    "main_sim_pkey" PRIMARY KEY, btree (id)
    "main_sim_FK_Numbers_id_key" UNIQUE, btree ("FK_Numbers_id")
    "main_sim_Iccid_key" UNIQUE, btree ("Iccid")
    "main_sim_FK_Device_id" btree ("FK_Device_id")
Foreign-key constraints:
    "FK_Device_id_refs_id_480a73d1" FOREIGN KEY ("FK_Device_id") REFERENCES main_device(id) DEFERRABLE INITIALLY DEFERRED
    "FK_Numbers_id_refs_id_380cb036" FOREIGN KEY ("FK_Numbers_id") REFERENCES main_number(id) DEFERRABLE INITIALLY DEFERRED

...我们可以看到该列存在。

可能是语法错误，但我看不到是什么...

任何帮助将不胜感激。 阿莱西奥

Answer 1

不，FK_Numbers_id 列不存在，只有"FK_Numbers_id" 列存在

显然您使用双引号创建了表，因此所有列名现在都区分大小写，您必须始终使用双引号：

select sim.id as idsim, 
       num.id as idnum 
from main_sim sim 
   left join main_number num on ("FK_Numbers_id" = num.id);

回顾一下documented in the manual：

foo 和 FOO 列相同，"foo" 和 "FOO" 列不同。