蟾蜍在蟾蜍中為oracle明確定義錯誤

Question

我在Toad for oracle中工作，並且編寫了此SQL查詢，但是它給出了錯誤：

[錯誤]執行（65：3）：ORA-00918：列定義不明確

以下是我嘗試提供別名以區分各列的SQL查詢。

 select HR.EMPLOYEES.FIRST_NAME||' '||HR.EMPLOYEES.LAST_NAME AS 
 Full_Name,HR.EMPLOYEES.SALARY as sal,HR.EMPLOYEES.JOB_ID as ji,
 HR.EMPLOYEES.COMMISSION_PCT as cmpct,HR.EMPLOYEES.MANAGER_ID as 
 mgid,HR.EMPLOYEES.DEPARTMENT_ID as dep,HR.DW_COUNTRIES.C_ID as 
 country,HR.DW_REGION.R_ID as region,
 HR.LOCATIONS.LOCATION_ID as loc
 from HR.EMPLOYEES
 join HR.DEPARTMENTS ON 
 HR.EMPLOYEES.DEPARTMENT_ID=HR.DEPARTMENTS.DEPARTMENT_ID
join HR.DEPARTMENTS ON HR.DEPARTMENTS.LOCATION_ID=HR.LOCATIONS.LOCATION_ID
join HR.LOCATIONS   ON HR.LOCATIONS.COUNTRY_ID=HR.DW_COUNTRIES.C_ID
join HR.DW_COUNTRIES ON HR.DW_COUNTRIES.R_ID=HR.DW_REGION.R_ID
where HR.DW_COUNTRIES.C_ID='US'
AND HR.EMPLOYEES.HIRE_DATE BETWEEN TO_DATE('16/08/2002','DD/MM/YYYY') AND 
TO_DATE('07/12/2007','DD/MM/YYYY')
AND HR.DW_REGION.R_ID=2
AND HR.LOCATIONS.LOCATION_ID=1700
AND HR.EMPLOYEES.DEPARTMENT_ID=90

Answer 1

您在查詢中兩次使用了表HR.DEPARTMENTS，這是問題的根源。 您絕對確定必須兩次加入此表嗎？ 您也有一些不清楚的聯接。 我修復了它們，但未測試查詢。

 select HR.EMPLOYEES.FIRST_NAME||' '||HR.EMPLOYEES.LAST_NAME AS 
 Full_Name,HR.EMPLOYEES.SALARY as sal,HR.EMPLOYEES.JOB_ID as ji,
 HR.EMPLOYEES.COMMISSION_PCT as cmpct,HR.EMPLOYEES.MANAGER_ID as 
 mgid,HR.EMPLOYEES.DEPARTMENT_ID as dep,HR.DW_COUNTRIES.C_ID as 
 country,HR.DW_REGION.R_ID as region,
 HR.LOCATIONS.LOCATION_ID as loc
 from HR.EMPLOYEES
 join HR.DEPARTMENTS ON 
 HR.EMPLOYEES.DEPARTMENT_ID=HR.DEPARTMENTS.DEPARTMENT_ID
join HR.LOCATIONS    ON HR.DEPARTMENTS.LOCATION_ID=HR.LOCATIONS.LOCATION_ID
join HR.DW_COUNTRIES ON HR.LOCATIONS.COUNTRY_ID=HR.DW_COUNTRIES.C_ID
join HR.DW_REGION    ON HR.DW_COUNTRIES.R_ID=HR.DW_REGION.R_ID
where HR.DW_COUNTRIES.C_ID='US'
AND HR.EMPLOYEES.HIRE_DATE BETWEEN TO_DATE('16/08/2002','DD/MM/YYYY') AND 
TO_DATE('07/12/2007','DD/MM/YYYY')
AND HR.DW_REGION.R_ID=2
AND HR.LOCATIONS.LOCATION_ID=1700
AND HR.EMPLOYEES.DEPARTMENT_ID=90