どのように私は結合をマージできますか？

Question

私は以下のクエリを実行しますが、パフォーマンスを向上させたいと考えています（パフォーマンスは賢明です）：

sentence_idと。 project_idはインデックスです。

ここでの目標は、同じテーブルの2つの結合を1つにマージしようとすることです（可能な場合） どうすればいいですか？

SELECT rs.project_id, 
       ms.id AS raw_sentence_id, 
       rs.sentence AS raw_sentence_text, 
       rs.sentence_id AS raw_sentence_text_id, 
       rst.tokens AS tokenization_information, 
       ns.sentence_id AS normalized_sentence_id, 
       ns.sentence AS normalized_sentence_text, 
       nst.token_indices 
      FROM manual_sentences ms 
      JOIN sentences rs ON (ms.original_sentence_id = rs.sentence_id AND rs.project_id = 623483) 
    LEFT JOIN sentence_tokens rst ON (ms.original_sentence_id = rst.sentence_id AND rst.project_id = 623483) 
      JOIN sentences ns ON (ms.sentence_id = ns.sentence_id AND ns.project_id = 623483) 
    LEFT JOIN sentence_tokens nst ON (ms.sentence_id = nst.sentence_id AND nst.project_id = 623483) 
    WHERE ms.project_id = 623483 

Answer 1

あなたは接続詞を使っていることを行うことができるはず：

SELECT rs.project_id, 
       ms.id AS raw_sentence_id, 
       rs.sentence AS raw_sentence_text, 
       rs.sentence_id AS raw_sentence_text_id, 
       rst.tokens AS tokenization_information, 
       ns.sentence_id AS normalized_sentence_id, 
       ns.sentence AS normalized_sentence_text, 
       nst.token_indices 
      FROM manual_sentences ms 
      JOIN sentences rs ON (ms.original_sentence_id = rs.sentence_id AND rs.project_id = 623483) 
    LEFT JOIN sentence_tokens rst ON (ms.original_sentence_id = rst.sentence_id AND ms.sentence_id = rst.sentence_id AND rst.project_id = 623483) 
      JOIN sentences ns ON (ms.sentence_id = ns.sentence_id AND ns.project_id = 623483) 
    WHERE ms.project_id = 623483