PART III:Thinking in Sets
CHAPTER7 Thinking in Sets
The three mostcommon set operations are as follows.
Intersection
Difference
Union
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在SQL中相应的关键词分别是 Intersection
Except
Union
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实际数据库实现一般支持以下相应的数据库集合操作 INNER JOIN
OUTER JOIN
UNION JOIN
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不过其区别是前者集合操作涉及表中所有列的值,而JOINs则只涉及到表中指定的列值.
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