为此,您可以使用COUNT()
方法。让我们首先创建一个表-
mysql> create table DemoTable -> ( -> EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> EmployeeName varchar(100) -> );
使用插入命令在表中插入一些记录-
mysql> insert into DemoTable(EmployeeName) values('John'); mysql> insert into DemoTable(EmployeeName) values('Carol'); mysql> insert into DemoTable(EmployeeName) values('David'); mysql> insert into DemoTable(EmployeeName) values('Carol'); mysql> insert into DemoTable(EmployeeName) values('Carol'); mysql> insert into DemoTable(EmployeeName) values('Bob'); mysql> insert into DemoTable(EmployeeName) values('Sam');
使用select语句显示表中的所有记录-
mysql> select *from DemoTable;
输出结果
这将产生以下输出-
+------------+--------------+ | EmployeeId | EmployeeName | +------------+--------------+ | 1 | John | | 2 | Carol | | 3 | David | | 4 | Carol | | 5 | Carol | | 6 | Bob | | 7 | Sam | +------------+--------------+ 7 rows in set (0.00 sec)
以下是查询以获取特定单词在MySQL中出现的次数。在这里,我们发现员工“ Carol”的出现-
mysql> select EmployeeName,count(EmployeeId) as Occurrence from DemoTable where EmployeeName='Carol';
输出结果
这将产生以下输出-
+--------------+------------+ | EmployeeName | Occurrence | +--------------+------------+ | Carol | 3 | +--------------+------------+ 1 row in set (0.05 sec)