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MySQL查询以获取值的计数并按降序在新列中显示计数

2024-04-23 15:45:02 372

与DESC一起使用ORDERBY以降序排列。要计算值，请使用COUNT()。例如，如果名称“John”出现在该列中三次，则在单独的列中将显示计数3，这样，所有计数值将使用ORDERBYDESC以降序排列。

让我们首先创建一个表-

mysql> create table DemoTable
   -> (
   -> EmployeeName varchar(100)
   -> );

使用插入命令在表中插入一些记录-

mysql> insert into DemoTable values('Sam');

mysql> insert into DemoTable values('David');

mysql> insert into DemoTable values('David');

mysql> insert into DemoTable values('Chris');

mysql> insert into DemoTable values('Robert');

mysql> insert into DemoTable values('Chris');

mysql> insert into DemoTable values('Sam');

mysql> insert into DemoTable values('Sam');

mysql> insert into DemoTable values('David');

mysql> insert into DemoTable values('Robert');

mysql> insert into DemoTable values('David');

mysql> insert into DemoTable values('Chris');

使用select语句显示表中的所有记录-

mysql> select *from DemoTable;

输出结果

+--------------+
| EmployeeName |
+--------------+
| Sam          |
| David        |
| David        |
| Chris        |
| Robert       |
| Chris        |
| Sam          |
| Sam          |
| David        |
| Robert       |
| David        |
| Chris        |
+--------------+
12 rows in set (0.00 sec)

以下是获取值计数并按降序在新列中显示计数的查询-

mysql> select EmployeeName,count(EmployeeName) as Total from DemoTable
   -> group by EmployeeName
   -> order by Total DESC;

输出结果

+--------------+-------+
| EmployeeName | Total |
+--------------+-------+
| David        | 4     |
| Chris        | 3     |
| Sam          | 3     |
| Robert       | 2     |
+--------------+-------+
4 rows in set (0.00 sec)

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MySQL查询以获取值的计数并按降序在新列中显示计数

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