一般後臺做報表什麼的，可能會用到

createTime ---- 建立時間， 就是你要對比的時間，表的欄位型別為 datetime

直接上程式碼

-- 查詢上週的資料 
-- SELECT count(id) as count FROM user WHERE YEARWEEK(date_format(createTime,'%Y-%m-%d')) = YEARWEEK(now())-1; 

-- 查詢這個周的資料
-- SELECT count(id) as count FROM user WHERE YEARWEEK(date_format(createTime,'%Y-%m-%d')) = YEARWEEK(now())

-- 查詢上個月的資料 
-- select count(id) as count from user where date_format(createtime,'%Y-%m')=date_format(DATE_SUB(curdate(), INTERVAL 1 MONTH),'%Y-%m') 

-- 查詢這個月的資料 
-- SELECT count(id) as count FROM user WHERE date_format(createtime,'%Y-%m')=date_format(now(),'%Y-%m');
-- select count(id) as count from `user` where DATE_FORMAT(createtime,'%Y%m') = DATE_FORMAT(CURDATE(),'%Y%m') ; 

-- 查詢距離當前現在6個月的資料 
-- select count(id) as count from user where createtime between date_sub(now(),interval 6 month) and now(); 

-- 查詢今天的資料
-- SELECT count(id) as count FROM user WHERE date_format(createtime,'%Y-%m-%d')=date_format(now(),'%Y-%m-%d');

-- 查詢昨天的資料
-- SELECT * FROM user WHERE TO_DAYS(NOW())-TO_DAYS(createTime) = 1

-- 今年的
-- select * from `user` where YEAR(createTime)=YEAR(NOW());
-- 去年的
-- select * from `user` where YEAR(createTime)=YEAR(NOW())-1;

-- 來一發集合的
select 
    t1.count as toDay,
    tt1.count as lastDay,
    t2.count as lastWeek,
    tt2.count as toWeek,
    t3.count as lastMonth,
    tt3.count as toMonth,
    t4.count as toYear,
    tt4.count as lastYear,
    t.count as total
    from 
(SELECT count(id) as count FROM user WHERE date_format(createtime,'%Y-%m-%d')=date_format(now(),'%Y-%m-%d')) t1,
(SELECT count(id) as count FROM user WHERE TO_DAYS(NOW())-TO_DAYS(createTime) = 1) tt1,
(SELECT count(id) as count FROM user WHERE YEARWEEK(date_format(createTime,'%Y-%m-%d')) = YEARWEEK(now())-1) t2,
(SELECT count(id) as count FROM user WHERE YEARWEEK(date_format(createTime,'%Y-%m-%d')) = YEARWEEK(now())) tt2,
(select count(id) as count from user where date_format(createtime,'%Y-%m')=date_format(DATE_SUB(curdate(), INTERVAL 1 MONTH),'%Y-%m')) t3,
(SELECT count(id) as count FROM user WHERE date_format(createtime,'%Y-%m')=date_format(now(),'%Y-%m')) tt3,
(select count(id) as count from `user` where YEAR(createTime)=YEAR(NOW())) t4,
(select count(id) as count from `user` where YEAR(createTime)=YEAR(NOW())-1) tt4,
(select count(id) as count from user) t
 

統計當前月，後12個月，各個月的資料

下面是建立對照檢視

CREATE
    ALGORITHM = UNDEFINED 
    DEFINER = `tyro`@`%` 
    SQL SECURITY DEFINER
VIEW `past_12_month_view` AS
    SELECT DATE_FORMAT(CURDATE(), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 1 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 2 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 3 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 4 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 5 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 6 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 7 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 8 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 9 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 10 MONTH), '%Y-%m') AS `month` 
    UNION SELECT DATE_FORMAT((CURDATE() - INTERVAL 11 MONTH), '%Y-%m') AS `month`
 

然後和你想要統計的表進行關聯查詢,如下的demo

select 
    v.month,
    ifnull(b.minute,0) count 
from 
    past_12_month_view v 
left join 
(select DATE_FORMAT(t.createTime,'%Y-%m') month,count(t.id) minute  from user t  group by month) b 
on 
    v.month = b.month 
group by 
    v.month

結果如下

順便把我上次遇到的一個排序小問題也寫出來

資料表有一個sort_num 欄位來代表排序，但這個欄位有些值是null，

現在的需求是

返回結果集按升序返回，如果sort_num 為null 則放在最後面

mysql null 預設是最小的值，如果按升序就會在前面

解決方法

SELECT * from table_name 
ORDER BY 
  case 
WHEN 
  sort_num is null 
  then 
    1 
  else 0 end, sort_num asc

搞定收工。。。。。