UNION ALLを使用したCASEのSQL ORDER BY

Question

PostgreSQL（7.4と8.x）を実行していて、これは動作していたと思っていましたが、今はエラーが発生しています。

私は別々にクエリを実行できますが、それは正常に動作しますが、UNIONまたはUNION ALLの場合はエラーがスローされます。

このエラーアウト：（警告：pg_query（）：クエリに失敗しました：ERROR：列 "フィールド1" が存在しません... ORDER CASE "フィールド1" W BY ...）

SELECT "Field1" AS field_1, "Field2" AS field_2, 
"Field3" AS field_3, "Field4" AS field_4 
FROM "TableName" 
WHERE condition 
AND other_condition 
UNION ALL 
SELECT "Field1" AS field_1, "Field2" AS field_2, 
"Field3" AS field_3, "Field4" AS field_4 
FROM "TableName" 
WHERE yet_another_condition 
AND yet_another_other_condition 
ORDER BY CASE "Field1" 
    WHEN 'A' THEN 1 
    WHEN 'B' THEN 2 
    WHEN 'C' THEN 3 
    ELSE 4 
END 

この作品：

SELECT "Field1" AS field_1, "Field2" AS field_2, 
"Field3" AS field_3, "Field4" AS field_4 
FROM "TableName" 
WHERE yet_another_condition 
AND yet_another_other_condition 
ORDER BY CASE "Field1" 
    WHEN 'A' THEN 1 
    WHEN 'B' THEN 2 
    WHEN 'C' THEN 3 
    ELSE 4 
END 

そして、これは同様に動作します：

SELECT "Field1" AS field_1, "Field2" AS field_2, 
"Field3" AS field_3, "Field4" AS field_4 
FROM "TableName" 
WHERE condition 
AND other_condition 
ORDER BY CASE "Field1" 
    WHEN 'A' THEN 1 
    WHEN 'B' THEN 2 
    WHEN 'C' THEN 3 
    ELSE 4 
END 

と私はORDER BYをオフのままにし、ちょうどすべてのIT UNIONまたはUNIONを使用している場合同様に動作します。

すべてのアイデア？他にすべてをかける

Answer 1

はSELECT：

SELECT * FROM (
    SELECT "Field1" AS field_1, "Field2" AS field_2, 
    "Field3" AS field_3, "Field4" AS field_4 
    FROM "TableName" 
    WHERE condition 
    AND other_condition 
    UNION ALL 
    SELECT "Field1" AS field_1, "Field2" AS field_2, 
    "Field3" AS field_3, "Field4" AS field_4 
    FROM "TableName" 
    WHERE yet_another_condition 
    AND yet_another_other_condition 
) As A 
ORDER BY CASE field_1 
    WHEN 'A' THEN 1 
    WHEN 'B' THEN 2 
    WHEN 'C' THEN 3 
    ELSE 4 
END 

や、より良いを、それはUNIONの終わりに渡されると、ORDER BYでエイリアスを使用します。

SELECT "Field1" AS field_1, "Field2" AS field_2, 
    "Field3" AS field_3, "Field4" AS field_4 
    FROM "TableName" 
    WHERE condition 
    AND other_condition 
    UNION ALL 
    SELECT "Field1" AS field_1, "Field2" AS field_2, 
    "Field3" AS field_3, "Field4" AS field_4 
    FROM "TableName" 
    WHERE yet_another_condition 
    AND yet_another_other_condition 
    ORDER BY CASE field_1 
    WHEN 'A' THEN 1 
    WHEN 'B' THEN 2 
    WHEN 'C' THEN 3 
    ELSE 4 
    END 

Answer 2

最初のものはありませんあなたは

ORDER BY CASE field_1 

に"Field1"を行う必要がありますので、動作しない単一サブクエリでのみ利用可能で、共通の別名でUNIONを作成した後は、その列を"Field1"として参照することはできません。