论文部分内容阅读
电脑知识与技术默认情况下,表中所有的行作为一个组处理。在SELECT语句中可以使用GROUPBY子句将行划分成较小的组。然后,使用聚组函数返回每一个组的汇总信息。另外,可以使用HAVING子句限制返回的结果集。GROUPBY子句可以将查询结果分组,并返回行的汇总信息。Oracle按照GROUPBY
Computer Knowledge and Technology By default, all rows in the table are treated as one group. You can use the GROUP BY clause in a SELECT statement to divide a row into smaller groups. Then, use the aggregate function to return summary information for each group. In addition, you can use the HAVING clause to limit the returned result set. The GROUP BY clause can group the query results and return summary information for the rows. Oracle according to GROUPBY