mysql - 修飾リストからの一時関係への参照

Question

このような SQL クエリを考えてみましょう

SELECT Temp.rating, Temp.avgage
FROM (SELECT S.rating, AVG (S.age) AS avgage
FROM Sailors S 
GROUP BY S.rating) AS Temp
WHERE Temp.avgage = (SELECT MIN (Temp.avgage)
FROM Temp)

MySQL モニターは次のエラーを返します。

エラー 1146 (42S02): テーブル 'testDB.Temp' が存在しません

このエラーを回避するにはどうすればよいですか?

Answer 1

SELECT Temp.rating, Temp.avgage 
FROM 
  ( SELECT S.rating, AVG(S.age) AS avgage
    FROM Sailors S 
    GROUP BY S.rating
  ) AS Temp
WHERE Temp.avgage = 
      ( SELECT MIN (Temp.avgage)
        FROM Temp                --- the error is here
      )

---

ネクタイの扱い方に応じて、次のものを使用できます。

SELECT Temp.rating, Temp.avgage 
FROM 
  ( SELECT S.rating, AVG(S.age) AS avgage
    FROM Sailors S 
    GROUP BY S.rating
  ) AS Temp
ORDER BY Temp.avgage 
LIMIT 1

またはより単純な同等物：

SELECT S.rating, AVG(S.age) AS avgage
FROM Sailors S 
GROUP BY S.rating
ORDER BY avgage 
LIMIT 1

---

またはこれ（すべてのタイの結果を表示します）：

SELECT Temp.rating, Temp.avgage 
FROM 
  ( SELECT S.rating, AVG(S.age) AS avgage
    FROM Sailors S 
    GROUP BY S.rating
  ) AS Temp
WHERE Temp.avgage = 
      ( SELECT AVG(S.age) AS avgage
        FROM Sailors S 
        GROUP BY S.rating
        ORDER BY avgage 
        LIMIT 1              
      )