有些函數一直未發現，知道經常才知道，愧疚啊
本季度的第一天 ，然后你可以把字符串再轉換為日期。 方法很多，包括同一個函數的別名（同義詞）也很多。比如CURDATE(),CURRENT_DATE(), CURRENT_DATE, NOW 等都可以返回當天
mysql教程> select CURDATE(),ELT(QUARTER(CURDATE()),
-> year(CURDATE())*1000+0101,
-> year(CURDATE())*1000+0401,
-> year(CURDATE())*1000+0701,
-> year(CURDATE())*1000+1001) as firstDayofQ;
+------------+-------------+
| CURDATE() | firstDayofQ |
+------------+-------------+
| 2009-05-19 | 2009401 |
+------------+-------------+
1 row in set (0.00 sec)
mysql>
用mysql語句獲取本季度的第一天
本月的第一天，
date(
concat(year(curdate()),'-',month(curdate()),'-','1'))
本周的第一天
curdate()-
WEEKDAY(curdate())
用mysql語句獲取本季度的第一天
date(
concat(year(curdate()),'-',
if(quarter(curdate())=1,1,if(quarter(curdate())=2,4,if(quarter(curdate())=3,7,10))
用mysql語句獲取本季度的第一天：
優化：
date(
concat(year(curdate()),'-',elt(quarter(curdate()),1,4,7,10),'-',1))
本周的第一天
date_add(date('2009-5-29'),INTERVAL -weekday('2009-5-29') day)
mysql 獲取當天發布文件內容sql語句
SELECT * FROM `p8_memberdata` where regdate BETWEEN (UNIX_TIMESTAMP(NOW())-86440) AND NOW()
SELECT * FROM `p8_memberdata` WHERE DATE_FORMAT(FROM_UNIXTIME(regdate),'%Y-%m-%d')= DATE_FORMAT(NOW(),'%Y-%m-%d') order by uid desc
某一天內某一帖的回復人數，排除同一個多次回復的情況
SELECT COUNT(DISTINCT author_id,subject_id,(DATE_FORMAT(`create_time` , '%Y-%m-%d'))) FROM COMMENT
WHERE subject_id IN (SELECT id FROM group_post WHERE group_id=5135203559277568 )
導出某個表里指定的記錄，命令行模式下導出：
mysqldump -h 127.0.0.1 -uroot -p123456 sns groups -x --where " id IN (SELECT groupid FROM activity_group)" > a.sql
查找表中當日插進的記錄
SELECT * FROM table_name WHERE DATEDIFF(create_time,NOW())=0