To understand how the optimizer ends up with 0.0014% as the filter factor, first look at the six elements in the IN list predicate.
为了了解优化器如何最终以 0.0014％作为过滤因子，首先要查看在IN清单谓词上的6 个元素。
Another way to use conditions is to apply a filter to a list of repeatable elements.
使用条件的另一方法是将筛选器应用到可重复元素的列表上，如第2部分中的“筛选数组”中所述。
Two particularly useful procedural list functions are filter and map . The filter function takes a list and removes those elements that fail to meet some specified criterion.
两个非常有用的过程列表函数是filter和map 。
Two particularly useful procedural list functions are filter and map . The filter function takes a list and removes those elements that fail to meet some specified criterion.
两个非常有用的过程列表函数是filter和map 。
应用推荐