MySql按周，按月，按日分组统计数据

知识关键词：DATE_FORMAT，在service层循环判断，补齐

1.  
   select DATE_FORMAT(create_time,'%Y') weeks,count(caseid) count from tc_case group by weeks;
2.  
   select DATE_FORMAT(create_time,'%Y%u') weeks,count(caseid) count from tc_case group by weeks;
3.  
   select DATE_FORMAT(create_time,'%Y%m%d') days,count(caseid) count from tc_case group by days;
4.  
   select DATE_FORMAT(create_time,'%Y%m') months,count(caseid) count from tc_case group by months;

    

DATE_FORMAT(date,format)

根据format字符串格式化date值。下列修饰符可以被用在format字符串中：

%M 月名字(January……December)
%W 星期名字(Sunday……Saturday)
%D 有英语前缀的月份的日期(1st, 2nd, 3rd, 等等。）
%Y 年, 数字, 4 位
%y 年, 数字, 2 位
%a 缩写的星期名字(Sun……Sat)
%d 月份中的天数, 数字(00……31)
%e 月份中的天数, 数字(0……31)
%m 月, 数字(01……12)
%c 月, 数字(1……12)
%b 缩写的月份名字(Jan……Dec)
%j 一年中的天数(001……366)
%H 小时(00……23)
%k 小时(0……23)
%h 小时(01……12)
%I 小时(01……12)
%l 小时(1……12)
%i 分钟, 数字(00……59)
%r 时间,12 小时(hh:mm:ss [AP]M)
%T 时间,24 小时(hh:mm:ss)
%S 秒(00……59)
%s 秒(00……59)
%p AM或PM
%w 一个星期中的天数(0=Sunday ……6=Saturday ）
%U 星期(0……52), 这里星期天是星期的第一天
%u 星期(0……52), 这里星期一是星期的第一天
%% 一个文字“%”。

mysql统计一年12个月的数据，当某个月没数据的时候自动补0

传值：

select 
ifnull(b.num,0),a.date
from 
(

SELECT CONCAT(#{year},'-01') AS date UNION
SELECT CONCAT(#{year},'-02') AS date UNION
SELECT CONCAT(#{year},'-03') AS date UNION
SELECT CONCAT(#{year},'-04') AS date UNION
SELECT CONCAT(#{year},'-05') AS date UNION
SELECT CONCAT(#{year},'-06') AS date UNION
SELECT CONCAT(#{year},'-07') AS date UNION
SELECT CONCAT(#{year},'-08') AS date UNION
SELECT CONCAT(#{year},'-09') AS date UNION
SELECT CONCAT(#{year},'-10') AS date UNION
SELECT CONCAT(#{year},'-11') AS date UNION
SELECT CONCAT(#{year},'-12') AS date

)a

left join

(select count(*) num,DATE_FORMAT(createDate,'%Y-%m')as date from c_item group by date) b
on a.date = b.date

查询本年，一条数据

select 
sum(case month(createDate) when '1' then 1 else 0 end) as 一月份,
sum(case month(createDate) when '2' then 1 else 0 end) as 二月份,
sum(case month(createDate) when '3' then 1 else 0 end) as 三月份,
sum(case month(createDate) when '4' then 1 else 0 end) as 四月份,
sum(case month(createDate) when '5' then 1 else 0 end) as 五月份,
sum(case month(createDate) when '6' then 1 else 0 end) as 六月份,
sum(case month(createDate) when '7' then 1 else 0 end) as 七月份,
sum(case month(createDate) when '8' then 1 else 0 end) as 八月份,
sum(case month(createDate) when '9' then 1 else 0 end) as 九月份,
sum(case month(createDate) when '10' then 1 else 0 end) as 十月份,
sum(case month(createDate) when '11' then 1 else 0 end) as 十一月份,
sum(case month(createDate) when '12' then 1 else 0 end) as 十二月份
from c_item
WHERE YEAR(createDate)=YEAR(NOW());