函数Oracle中常用的统计函数简单而有效的数据分析工具

在Oracle数据库中，有许多常用的统计函数可以帮助我们进行数据分析，这些函数简单易用，可以快速地获取所需的统计数据，以下是一些常用的统计函数及其功能：

1、COUNT(*)

用途：计算表中的记录数。

语法：SELECT COUNT(*) FROM table_name;

2、SUM(column_name)

用途：计算指定列的总和。

语法：SELECT SUM(column_name) FROM table_name;

3、AVG(column_name)

用途：计算指定列的平均值。

语法：SELECT AVG(column_name) FROM table_name;

4、MIN(column_name)

用途：计算指定列的最小值。

语法：SELECT MIN(column_name) FROM table_name;

5、MAX(column_name)

用途：计算指定列的最大值。

语法：SELECT MAX(column_name) FROM table_name;

6、GROUP BY

用途：根据指定的列对数据进行分组。

语法：SELECT column_name, function_name(column_name) FROM table_name GROUP BY column_name;

7、HAVING

用途：对分组后的数据进行筛选。

语法：SELECT column_name, function_name(column_name) FROM table_name GROUP BY column_name HAVING condition;

8、RANK() OVER (ORDER BY column_name)

用途：为排序后的记录分配排名。

语法：SELECT column_name, RANK() OVER (ORDER BY column_name) AS rank FROM table_name;

9、DENSE_RANK() OVER (ORDER BY column_name)

用途：为排序后的记录分配排名，相同值的记录具有相同的排名。

语法：SELECT column_name, DENSE_RANK() OVER (ORDER BY column_name) AS dense_rank FROM table_name;

10、NTILE(n) OVER (ORDER BY column_name)

用途：将排序后的记录分为n个组。

语法：SELECT column_name, NTILE(n) OVER (ORDER BY column_name) AS ntile FROM table_name;

11、PERCENTILE_CONT(percentile) WITHIN GROUP (ORDER BY column_name) OVER () AS percentile_cont

用途：计算指定百分位数的值。

语法：SELECT PERCENTILE_CONT(percentile) WITHIN GROUP (ORDER BY column_name) OVER () AS percentile_cont FROM table_name;

12、PERCENTILE_DISC(percentile) WITHIN GROUP (ORDER BY column_name) OVER () AS percentile_disc

用途：计算指定百分位数的值，与PERCENTILE_CONT不同，PERCENTILE_DISC返回的是离散值。

语法：SELECT PERCENTILE_DISC(percentile) WITHIN GROUP (ORDER BY column_name) OVER () AS percentile_disc FROM table_name;