数据库结构 [code lang=“sql”] mysql> describe users; +———-+———-+——+—–+———+——-+ | Field    | Type     | Null | Key | Default | Extra | +———-+———-+——+—–+———+——-+ | username | char(30) | NO   | MUL | NULL    |       | | password | char(30) | NO   | MUL | NULL    |       | | email    | char(30) | NO   | MUL | NULL    |       | +———-+———-+——+—–+———+——-+ [/code] 统计相同password个数并降序： [code lang=“sql”]SELECT password,count(*) as num FROM users group by password order by num DESC;[/code]

统计相同password个数并降序，把前100项导出为excel [code lang=“sql”]SELECT password,count(*) as num  into outfile ‘top100.xls’ FROM users group by password order by num DESC limit 0,100;[/code]

附： mssql导出数据为excel [code lang=“sql”]EXEC master..xp_cmdshell ‘bcp tt.dbo.user out D:data.xls -c -q -S “localhost” -U “sa” -P “123456”’[/code] mssql删除文件 [code lang=“sql”]EXEC master..xp_cmdshell ‘del D:data.xls’[/code]