MySQL查询对以特定字母开头的记录进行计数
让我们首先创建一个表-
mysql> create table DemoTable775 ( FirstName varchar(100) );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable775 values('Adam') ;
mysql> insert into DemoTable775 values('Carol');
mysql> insert into DemoTable775 values('John');
mysql> insert into DemoTable775 values('Sam');
mysql> insert into DemoTable775 values('Adan');使用select语句显示表中的所有记录-
mysql> select *from DemoTable775;
这将产生以下输出-
+-----------+ | FirstName | +-----------+ | Adam | | Carol | | John | | Sam | | Adan | +-----------+ 5 rows in set (0.00 sec)
以下是查询以特定字母开头的记录的查询-
mysql> select count(*),substring(FirstName,1,2) from DemoTable775 group by substring(FirstName,1,2);
这将产生以下输出-
+----------+--------------------------+ | count(*) | substring(FirstName,1,2) | +----------+--------------------------+ | 2 | Ad | | 1 | Ca | | 1 | Jo | | 1 | Sa | +----------+--------------------------+ 4 rows in set (0.00 sec)