sql语句错误：“列..不存在”

Question

我尝试从postgres控制台执行此命令：

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

我得到了这样的答复：

ERROR:  column "fk_numbers_id" does not exist
LINE 1: ...m from main_sim sim left join main_number num on (FK_Numbers...

但如果我只是用以下方式检查我的桌子：

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

...因为我们可以看到该列存在。

可能是它的语法错误，但我无法看到...

任何帮助都将受到赞赏。 Alessio的

Answer 1

不，列FK_Numbers_id不存在，只有列"FK_Numbers_id"存在

显然，您使用双引号创建了表格，因此所有列名称现在都区分大小写，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);

重温已经documented in the manual的内容：

列foo和FOO相同，列"foo"和"FOO"不相同。