隐式事务,mysql查询最近7天的数据
with cte as
(
select belongsAgent from [QPProxyDB].[dbo].[BS_ProxyInfo] where ProxyID = @ProxyID 
union all
select a.ProxyID from [QPProxyDB].[dbo].[BS_ProxyInfo] a join cte b on a.ProxyID = b.belongsAgent
)
select * from cte order by belongsAgent asc

语句迭代迭代:SET
IMPLICIT_TRANSACTIONS { ON | OFF
}

解决思路

  1. 思路一: 可以在自己的程序中做额外的补零处理

  2. 思路二: 构建一个最近七天的结果集,然后和查询的结果集合做left
    join(本文采用第二种方式)

select a.click_date,b.count
from (
    SELECT curdate() as click_date
    union all
    SELECT date_sub(curdate(), interval 1 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 2 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 3 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 4 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 5 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 6 day) as click_date
) a left join (
  select date(create_time) as datetime, count(*) as count
  from arms_task
  group by date(create_time)
) b on a.click_date = b.datetime;

当天2017-08-28结果显示为NULL

图片 1

需要把NULL设置为0,利用ifnull函数即可

select a.click_date,ifnull(b.count,0) as count
from (
    SELECT curdate() as click_date
    union all
    SELECT date_sub(curdate(), interval 1 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 2 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 3 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 4 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 5 day) as click_date
    union all
    SELECT date_sub(curdate(), interval 6 day) as click_date
) a left join (
  select date(create_time) as datetime, count(*) as count
  from arms_task
  group by date(create_time)
) b on a.click_date = b.datetime;

 

图片 2

 

隐式事务无需显示开始:不用 Begin
Transaction,必须显示结束:以 Commit Transaction
或者 Rollback
Transaction 方式结束。

问题描述

查询数据库表中最近7天的记录

select count(*),date(create_time) as date from task where datediff(now(),create_time)<=6  group by day(create_time); 

 

但是发现某一天没有数据,结果中没有显示当天(2017-08-28)的数据

图片 3

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