mysql中关于分组的使用

2. 
   
   select DATE_FORMAT(create_time,'%Y%u') weeks,count(caseid) count from tc_case group by weeks;
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   select DATE_FORMAT(create_time,'%Y%m%d') days,count(caseid) count from tc_case group by days;
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   select DATE_FORMAT(create_time,'%Y%m') months,count(caseid) count from tc_case group by months;
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6. 
   
   1、按照月份：
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   select sum(total_amount) as total, date_format(stat_date, '%Y-%m') from week_report WHERE `stat_date` BETWEEN '2016-11-02' AND '2017-04-30' group by date_format(stat_date, '%Y-%m');
8. 
   
   select sum(total_amount) as total,date_format(stat_date, '%Y-%m') from week_report WHERE `stat_date` BETWEEN '2016-12-11' AND '2016-12-22' group by date_format(stat_date, '%Y-%m');
9. 
   
   获得按照月份分组进行汇总的数据。
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11. 
    
    concat()连接字符串
12. 
    
13. 
    
    -- month
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    select CONCAT(YEAR(stat_date),'_',DATE_FORMAT(stat_date,'%m')) months ,sum(total_amount) as count_amount, sum(total_new_user) as count_new_user, sum(da_active_user) as count_active_user from xxx
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    WHERE `stat_date` BETWEEN '2016-01-02' AND '2017-05-30' group by months;
16. 
    
17. 
    
    -- 季度
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    select CONCAT(YEAR(stat_date),'_',quarter(stat_date)) qu,sum(total_amount) as count_amount, sum(total_new_user) as count_new_user, sum(da_active_user) as count_active_user from xxx
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    WHERE `stat_date` BETWEEN '2016-01-02' AND '2017-05-30' group by qu;
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21. 
    
    -- 周
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    select CONCAT(YEAR(stat_date),'_',DATE_FORMAT(stat_date,'%U')) weeks,sum(total_amount) as count_amount, sum(total_new_user) as count_new_user, sum(da_active_user) as count_active_user from xxx
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    WHERE `stat_date` BETWEEN '2016-01-02' AND '2017-05-30' group by weeks;
24. 
    
25. 
    
    -- 天
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    select CONCAT(YEAR(stat_date),'_',DATE_FORMAT(stat_date,'%m'),'_',DATE_FORMAT(stat_date,'%d')) days, sum(total_amount) as count_amount, sum(total_new_user) as count_new_user, sum(da_active_user) as count_active_user from xxx
27. 
    
    WHERE `stat_date` BETWEEN '2016-01-02' AND '2017-05-30' group by days
28. 聊天界面代码java java实现聊天功能窗口

    大家都知道java中的图形界面设计，下面我就来给大家演示一下聊天窗口的设计，首先我们的目标是设计成这样：通过分析我们不难发现图形中有下拉框，文本框，按钮，文本域等，下面请看代码：package com.i; import java.awt.*; import javax.swing.*; public class Calculator extends JFrame{ //继承JFra