获取表中两组不同行的计数，然后在MySQL中进行划分
为此，请使用count（*）并将两个不同的行集的计数相除。让我们首先创建一个表-
mysql> create table DemoTable(isMarried tinyint(1));
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable values(1); mysql> insert into DemoTable values(0); mysql> insert into DemoTable values(1); mysql> insert into DemoTable values(1); mysql> insert into DemoTable values(1);
使用select语句显示表中的所有记录-
mysql> select *from DemoTable;
这将产生以下输出-
+-----------+ | isMarried | +-----------+ | 1 | | 0 | | 1 | | 1 | | 1 | +-----------+ 5 rows in set (0.00 sec)
以下是查询以获取表中两组不同行的计数，然后将它们除以-
mysql> select
(
select count(*) from DemoTable where isMarried=1) /
(
select count(*) from DemoTable where isMarried=0
) AS divide from dual;这将产生以下输出-
+--------+ | divide | +--------+ | 4.0000 | +--------+ 1 row in set (0.00 sec)