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SQL GROUP BY 详解及简单实例
GROUP BY 语句用于结合 Aggregate 函数，根据一个或多个列对结果集进行分组。SQL GROUP BY 语法SELECT column_name, aggregate_function(column_name)FROM
GROUP BY 语句用于结合 Aggregate 函数，根据一个或多个列对结果集进行分组。SQL GROUP BY 语法SELECT column_name, aggregate_function(column_name)FROM
