sql性能范例(sql performance)

oracle sql性能实例：

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1.需求是取11至100的记录.

性能差一点的sql

• SELECT *? FROM (SELECT row_.*, ROWNUM rownum_
  ???????? ? ? ? ? ? ? ? ? ? ? ?? FROM (SELECT users.id,users.name? FROM my.users users0_) row_ )

????????? WHERE rownum_ <= 100 AND rownum_ > 10

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性能优良的sql应该是：

• SELECT *? FROM (SELECT row_.*, ROWNUM rownum_? FROM (SELECT users.id,users.name
  ????????????????? FROM my.users users0_) row_ where rownum <= 100 )
  ?WHERE rownum_ > 10

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