August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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144
｜
第
16
章
notInner
（非内连接）
除了不返回满足连接条件的记录之外，非内连接返回与全连接相同的数据（见
图
16-22
）。
图
16
-
22
：notInner（非内连接）
与全连接一样，我在图
16-23
中为
notInner
（非内连接）保留了重复的
Category
字段，以突出其输出与前述连接类型的不同。
图
16
-
23
：notInner（非内连接）的结果
16.4
何时使用每种连接类型
仅仅因为一个连接返回了正确的记录数，并不意味着连接运用是正确的。在选择连
接条件和连接类型时，必须仔细思考将要包含和排除哪些数据。
让我们考虑一些需要特定连接类型的情况：
inner
（内连接）
内连接是连接技术的主力军。你可以用它来过滤缺失的记录，这些记录会在左
连接或右连接中作为空值返回，从而保护只需要非空值的计算。
notInner
（非内连接）
表面看起来这是一种奇怪的连接类型。为什么要把两个由于不符合指定的连接
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