Question

在试图随时间推移提出机票状况的观点时,我面临几个挑战:

背景:

载有机票记录的数据库是为了进行基本重新计算,其中包括以下各栏(我认为是相关的):

- 地位——日期:修改

希望的解决办法:

A table which includes: The count of each status grouped by week/month/year.

挑战:

不包括地位没有改变的任何修订。

Thanks prior to time for any assistance, this is取而代之:

Answer 1

Should be something like this (without the grouping by date):

 SELECT t1.*
 FROM table as t1
 JOIN table as t2 ON (t1.original = t2.ID)
 WHERE t1.status != t2.status;

Answer 2

http://dev.mysql.com/doc/refman/5.5/en/exists-and-not-exists-subqueries.html” rel=“nofollow”EXISTS/。