MySQLの改善選択ジャンクションテーブルクエリ

Question

私は次の動作を取得しようとしている

：3つの表は、以下のように定義されている

+-----+--------------+-----+-----+-----+-------+-------+-------+--------+--------+ 
| id | name   | hp | atk | def | spatk | spdef | speed | type1 | type2 | 
+-----+--------------+-----+-----+-----+-------+-------+-------+--------+--------+ 
| 1 | Bulbasaur | 45 | 49 | 49 | 65 | 65 | 45 | GRASS | POISON | 
| 2 | Ivysaur  | 60 | 62 | 63 | 80 | 80 | 60 | GRASS | POISON | 
| 3 | Venusaur  | 80 | 82 | 83 | 100 | 100 | 80 | GRASS | POISON | 
+-----+--------------+-----+-----+-----+-------+-------+-------+--------+--------+ 

：

pokedex: 
+----+------------+----+-----+-----+-------+-------+-------+ 
| id | name  | hp | atk | def | spatk | spdef | speed | 
+----+------------+----+-----+-----+-------+-------+-------+ 
| 1 | Bulbasaur | 45 | 49 | 49 | 65 | 65 | 45 | 
| 2 | Ivysaur | 60 | 62 | 63 | 80 | 80 | 60 | 
| 3 | Venusaur | 80 | 82 | 83 | 100 | 100 | 80 | 
+----+------------+----+-----+-----+-------+-------+-------+ 

poke_type: 
+------------+---------+ 
| pokedex_id | type_id | 
+------------+---------+ 
|   1 |  13 | 
|   1 |  5 | 
|   2 |  13 | 
|   2 |  5 | 
+------------+---------+ 

type: 
+----+----------+ 
| id | name  | 
+----+----------+ 
| 1 | NONE  | 
| 5 | POISON | 
| 13 | GRASS | 
+----+----------+ 

ことが知られています、各pokedexエントリー仲間と2 typeはpoke_typeテーブルにあります。私は次のようなクエリを作成しようとしました：

USE pokemon; 
SELECT dex.*, 
     t1.name AS type1, 
     t2.name AS type2 
FROM pokedex AS dex, 
    (SELECT pt.pokedex_id AS dexid, t.name AS name 
    FROM pokedex AS d 
      INNER JOIN poke_type AS pt ON d.id = pt.pokedex_id 
      INNER JOIN type as t ON pt.type_id = t.id 
    ) AS t1, 
    (SELECT pt.pokedex_id AS dexid, t.name AS name 
    FROM pokedex AS d 
      INNER JOIN poke_type AS pt ON d.id = pt.pokedex_id 
      INNER JOIN type as t ON pt.type_id = t.id 
    ) AS t2 
WHERE dex.id = t1.dexid AND dex.id = t2.dexid AND t1.name <> t2.name 
GROUP BY dex.id -- remove duplicates 

これは醜いクエリであり、おそらく効率的ではありません。どのようにこのクエリを改善するか/別の方法で選択する上の任意のアイデア？

Answer 1

それはTYPE1で、どのタイプがタイプ2でどのタイプのあなたのために重要ではありません場合は、これはおそらくあなたが得ることができる最も簡単です：

SELECT 
    dex.*, 
    MAX(t.name) AS type1, 
    MIN(t.name) AS type2 
FROM 
    pokedex AS dex 
    JOIN poke_type AS pt ON dex.id = pt.pokedex_id 
    JOIN type as t ON pt.type_id = t.id 
GROUP BY dex.id 

sqlfiddle