Oracle: 执行计划中的Nested Loops

一个Nested Loops操作总是有两个孩子,第一个孩子(即较上面的那行)叫outer loop,第二个叫inner loop


   1. 执行outer loop, 返回rowSet-outer

   2. for every row in rowSet-outer

          执行inner loop

      end for

   3. 将inner loop多次操作产生的结果总集返回给父操作,即Nested Loops操作

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