Oracle SQL join 注意事項意事項
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測試資料來源請先參考 Oracle DB 目錄
column ambiguously defined
欄位模棱兩可問題
例:
SELECT
employee_id,
department_name,
department_id
FROM
employees INNER JOIN departments
ON ( employees.department_id = departments.department_id);
錯誤:
ORA-00918: column ambiguously defined
00918. 00000 - "column ambiguously defined"
其問題:
在 department_id
因為不知道要顯示employees還是departments的department_id
解法:指定來源表格
SELECT
employee_id,
department_name,
employees.department_id
FROM
employees INNER JOIN departments
ON ( employees.department_id = departments.department_id);
測試:
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