如何在 MySQL 中实现按范围分组?
mysqlmysqli database
要在 MySQL 中按范围分组，我们首先创建一个表。创建表的查询如下
mysql> create table GroupByRangeDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > YourRangeValue int - > ); Query OK, 0 rows affected (0.78 sec)
现在您可以使用 insert 命令在表中插入一些记录。
查询如下
mysql> insert into GroupByRangeDemo(YourRangeValue) values(1); Query OK, 1 row affected (0.14 sec) mysql> insert into GroupByRangeDemo(YourRangeValue) values(7); Query OK, 1 row affected (0.15 sec) mysql> insert into GroupByRangeDemo(YourRangeValue) values(9); Query OK, 1 row affected (0.14 sec) mysql> insert into GroupByRangeDemo(YourRangeValue) values(23); Query OK, 1 row affected (0.13 sec) mysql> insert into GroupByRangeDemo(YourRangeValue) values(33); Query OK, 1 row affected (0.15 sec) mysql> insert into GroupByRangeDemo(YourRangeValue) values(35); Query OK, 1 row affected (0.16 sec) mysql> insert into GroupByRangeDemo(YourRangeValue) values(1017); Query OK, 1 row affected (0.11 sec)
使用 select 语句显示表中的所有记录。
查询如下
mysql> select *from GroupByRangeDemo;
以下是输出 −
+----+----------------+ | Id | YourRangeValue | +----+----------------+ | 1 | 1 | | 2 | 7 | | 3 | 9 | | 4 | 23 | | 5 | 33 | | 6 | 35 | | 7 | 1017 | +----+----------------+ 7 rows in set (0.04 sec)
这是按范围分组的查询
mysql> select round(YourRangeValue / 10), count(YourRangeValue) from GroupByRangeDemo where YourRangeValue < 40 group by round(YourRangeValue / 10) - > union - > select '40+', count(YourRangeValue) from GroupByRangeDemo where YourRangeValue >= 40;
以下是输出 −
+----------------------------+-----------------------+ | round(YourRangeValue / 10) | count(YourRangeValue) | +----------------------------+-----------------------+ | 0 | 1 | | 1 | 2 | | 2 | 1 | | 3 | 1 | | 4 | 1 | | 40+ | 1 | +----------------------------+-----------------------+ 6 rows in set (0.08 sec)
