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在许多相邻行上使用WHERe的Postgres查询痛苦得很慢

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在许多相邻行上使用WHERe的Postgres查询痛苦得很慢

我建议使用现代的连接语法,它可以很好地解决此问题:

SELECt  c1.source, c1.word,  c2.word, c3.word,  c4.word, c4.lemma, c4.pos, c5.word, c6.word, c7.word, c8.word, c9.word, c9.lemma, c9.pos, c10.word, c11.wordFROM orderedflatcorpus AS c1JOIN orderedflatcorpus AS c2 ON c1.id + 1 = c2.idJOIN orderedflatcorpus AS c3 ON c1.id + 2 = c3.id JOIN orderedflatcorpus AS c4 ON c1.id + 3 = c4.idJOIN orderedflatcorpus AS c5 ON c1.id + 4 = c5.idJOIN orderedflatcorpus AS c6 ON c1.id + 5 = c6.idJOIN orderedflatcorpus AS c7 ON c1.id + 6 = c7.idJOIN orderedflatcorpus AS c8 ON c1.id + 7 = c8.idJOIN orderedflatcorpus AS c9 ON c1.id + 8 = c9.idJOIN orderedflatcorpus AS c10 ON c1.id + 9 = c10.idJOIN orderedflatcorpus AS c11 ON c1.id + 10 = c11.idWHERe c4.pos LIKE 'v%'AND c5.pos = 'appge'AND c6.lemma = 'way'AND c7.pos LIKE 'i%'AND c8.word = 'the'AND c9.pos LIKE 'n%'

笔记:

  • 多余
    LIKE
    的已删除
  • ORDER BY
    删除,因为它非常昂贵。CSV(如表格行)不需要排序即可生效。如果绝对需要排序,请在执行查询后使用命令行工具对其进行排序。


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