MySQL COUNT SUM
select
count(*) as mcount ,
left(create_time,10) as ptime ,
count(if(receive_msg is null,id,null)) as nullcount ,
count(if(receive_msg = '1',receive_msg,null)) as apfcount ,
count(if(receive_msg = '2',receive_msg,null)) as dttcount ,
count(if(receive_msg = '3',receive_msg,null)) as dicount
from
t_votes
where
left(create_time,7)>='$pearly'
and
left(create_time,7)<='$plate'
group by
ptime ;
COUNT(*)带上值为NULL的
COUNT(table_name)不带值为NULL的
计数不求和,可用其他字段替代
select
count(*) as mcount ,
left(create_time,10) as ptime ,
SUM(if(receive_msg is null,id,0)) as nullcount ,
SUM(if(receive_msg = '1',receive_msg,0)) as apfcount ,
SUM(if(receive_msg = '2',receive_msg,0)) as dttcount ,
SUM(if(receive_msg = '3',receive_msg,0)) as dicount
from
t_votes
where
left(create_time,7)>='$pearly'
and
left(create_time,7)<='$plate'
group by
ptime ;
SUM求和,最后一个参数改为0.具体原因不明
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作者: 王者之剑(http://www.albertsong.com/) 日期: 2008-01-05 22:10
字体大小: 小 中 大
示例演示了用C#操作MySQL的方法，提供了三个可重用的类MySqlDBUtil,MySqlPageUtil,Page。
本示例由 C#操作Access数据库的简单例子（http://www.albertsong.com/read-56.html）修改而来。
1.首先下� ......
一、连接MYSQL。
格式： mysql –h主机地址 –u用户名 －p用户密码
1、例1：连接到本机上的MYSQL。
首先在打开DOS窗口，然后进入目录 mysqlbin，再键入命令mysql -uroot -p，回车后提示你输密码，如果刚安装好MYSQL，超级用户root是没有密码的，故直接回车即可进入到MYSQL中了，MYSQL的提示符是： ......
1.CREATE USER
CREATE USER user [IDENTIFIED BY [PASSWORD] 'password']
[, user [IDENTIFIED BY [PASSWORD] 'password']] ...
CREATE USER用于创建新的MySQL账户。要使用CREATE USER，您必须拥有mysql数据库的全局CREATE USER权限，或拥有INSERT权限。对于每个账户，CREATE USER会在没有权限的mysq ......
1.JBPM4.3下载(http://sourceforge.net/projects/jbpm)
2.ant安装:jBPM下载包install目录中有一个ant的build.xml文件,使用ant -p你可以看到所有的安装
demo.setup.jboss：安装jboss，把jbpm安装到jboss中， 启动jboss，创建jbpm数据库表结构，部署实例，加载实例身份认证信息， 安装并启动eclipse
&n ......
一、创建用户的命令
mysql> create user 'username'@'localhost' identified by 'password';
Query OK, 0 rows affected (0.06 sec)
二、给新加用户授予权限
mysql> grant all privileges on test.* to 'username'@'localhost';
Query OK, 0 rows affected (0.00 sec)
说明：这条命令授予 username 对数据库 te ......
