sql - ORA-00904: 标识符无效

Question

我尝试使用 Oracle 数据库编写以下内部连接查询:

 SELECT Employee.EMPLID as EmpID, 
        Employee.FIRST_NAME AS Name,
        Team.DEPARTMENT_CODE AS TeamID, 
        Team.Department_Name AS teamname
 FROM PS_TBL_EMPLOYEE_DETAILS Employee
 INNER JOIN PS_TBL_DEPARTMENT_DETAILS Team 
 ON Team.DEPARTMENT_CODE = Employee.DEPTID

出现以下错误:

 INNER JOIN PS_TBL_DEPARTMENT_DETAILS Team ON Team.DEPARTMENT_CODE = Employee.DEPTID
                                              *
ERROR at line 4:
ORA-00904: "TEAM"."DEPARTMENT_CODE": invalid identifier

一张表的DDL为:

CREATE TABLE "HRMS"."PS_TBL_DEPARTMENT_DETAILS"
(
  "Company Code" VARCHAR2(255),
  "Company Name" VARCHAR2(255),
  "Sector_Code" VARCHAR2(255),
  "Sector_Name" VARCHAR2(255),
  "Business_Unit_Code" VARCHAR2(255),
  "Business_Unit_Name" VARCHAR2(255),
  "Department_Code" VARCHAR2(255),
  "Department_Name" VARCHAR2(255),
  "HR_ORG_ID" VARCHAR2(255),
  "HR_ORG_Name" VARCHAR2(255),
  "Cost_Center_Number" VARCHAR2(255),
  " " VARCHAR2(255)
)
SEGMENT CREATION IMMEDIATE PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS

Answer 1

你的问题是那些有害的双引号。

SQL> CREATE TABLE "APC"."PS_TBL_DEPARTMENT_DETAILS"
  2  (
  3    "Company Code" VARCHAR2(255),
  4    "Company Name" VARCHAR2(255),
  5    "Sector_Code" VARCHAR2(255),
  6    "Sector_Name" VARCHAR2(255),
  7    "Business_Unit_Code" VARCHAR2(255),
  8    "Business_Unit_Name" VARCHAR2(255),
  9    "Department_Code" VARCHAR2(255),
 10    "Department_Name" VARCHAR2(255),
 11    "HR_ORG_ID" VARCHAR2(255),
 12    "HR_ORG_Name" VARCHAR2(255),
 13    "Cost_Center_Number" VARCHAR2(255),
 14    " " VARCHAR2(255)
 15  )
 16  /

Table created.

SQL>

Oracle SQL 允许我们忽略数据库对象名称的大小写，前提是我们创建的名称全部为大写，或者不使用双引号。如果我们在脚本中使用混合大小写或小写字母并将标识符用双引号括起来，那么每当我们引用对象或其属性时，我们就注定要使用双引号和精确的大小写:

SQL> select count(*) from PS_TBL_DEPARTMENT_DETAILS
  2  where Department_Code = 'BAH'
  3  /
where Department_Code = 'BAH'
      *
ERROR at line 2:
ORA-00904: "DEPARTMENT_CODE": invalid identifier


SQL> select count(*) from PS_TBL_DEPARTMENT_DETAILS
  2  where "Department_Code" = 'BAH'
  3  /

  COUNT(*)
----------
         0

SQL>

---

tl;dr

不要在 DDL 脚本中使用双引号

(我知道大多数第三方代码生成器都这样做，但他们有足够的纪律将所有对象名称都大写。)

---

反之亦然。如果我们在不使用双引号的情况下创建表格......

create table PS_TBL_DEPARTMENT_DETAILS
( company_code VARCHAR2(255),
  company_name VARCHAR2(255),
  Cost_Center_Number VARCHAR2(255))
;

…我们可以在任何情况下引用它和它的列:

select * from ps_tbl_department_details

……或者

select * from PS_TBL_DEPARTMENT_DETAILS;

……或者

select * from PS_Tbl_Department_Details
where COMAPNY_CODE = 'ORCL'
and cost_center_number = '0980'