逐月

select max(record_id),record_name,user_id from sc_records group by user_id order by null.SQL Show most recent record in GROUP BY?Retrieving the last record in each group - MySQL

logstash Error: com.mariadb.jdbc.Driver not loadedCannot load driver class: com.mysql.jdbc.Driver Spring

参考 Ranked search with SQL计算term的出现次数。SELECT SUM(((LENGTH(Body) - LENGTH(REPLACE(Body, 'term', '')))/4)) AS Occurrences以次数进行排序。SELECT SUM(((LENGTH(Body) - LENGTH(REPLACE(Body, 'term', '')))/4) ...

mysql Date Time queryDate query'2018''2018-09''2018-09-01'2018-092018-09-0109201820180920180901如 select * from avaliable_times where course_date = 2018; Time query'08:00:00''08'08...

转自：https://www.cnblogs.com/roadofstudy/p/7446690.html最近在ubuntu系统上安装了MySQL，但是安装时没有提示输入root用户密码，在网上找了一天解决方案，试图修改root用户下的登入密码，但是网上的帖子都不凑效，最后终于改成功了，因此记下来以供有同样需要的人参考。1、安装$ sudo apt-get install mysql-...

只要索引中的unique index allows duplicates if at least one of the columns is null.refer to unique index allows duplicates if at least one of the columns is null.