Mysql分組查詢group by語句詳解

(1) group by的含義:將查詢結果按照1個或多個字段進行分組，字段值相同的爲一組 (2) group by可用於單個字段分組，也可用於多個字段分組函數 select * from employee; +------+------+--------+------+------+-------------+ | num | d_id | name | age | sex | homeaddr

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