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CREATE TABLE `user` (
  `id` int(5) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(10) DEFAULT NULL,
  `password` varchar(10) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=latin1
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1 name1 123456
2 name2 123456
3 name3 123456
4 name4  NULL
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£¨1£©select count(*) from `user`
£¨2£©select count(name) from `user`
£¨3£©select count(password) from `user`
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£¨2£©count(column_name)ÊǶÔÁÐÖв»Îª¿ÕµÄÐнøÐмÆÊý£¬ËùÒÔcount(name)=4£¬¶øcount(password)=3


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MySqlµÄ±íÀàÐÍ

create database sample;
create table 't_user' (
    'id' int(11) not null auto_increment,
    'name' varchar(100) not null default '',
    primary key ('id')
) type=myisam;
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ISAM Ô­À´µÄ±í´¦ÀíÆ ......

mysql ÖеÄ×Ö·û´®Á¬½Ó CONCAT(str1,str2,...)

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mysql> select CONCAT('My', 'S', 'QL');
-> 'MySQL'
mysql> select CONCAT('My', NULL, 'QL');
-> NULL
mysql> select CONCAT(14.3);
-> '14.3'
È磺update test set ......

Mysql ¸´ÖÆ±í¼°½á¹¹

Ò»¡¢CREATE TABLE ·½·¨
Õû±í¸´ÖÆ # create table бí select * from ¾É±í;
½á¹¹¸´ÖÆ # create table бí select * from ¾É±í where 1<>1;
¶þ¡¢INSERT INTO ·½·¨
µÃµ½½¨±íÓï¾ä # show create table ¾É±í;
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¸´ÖÆÊý¾Ýµ½Ð±í INSERT INTO new_table(col1,col2,...) (SELECT col1,col2,... from old_table); ......

MySQLÃüÁî

1. Á¬½Ómysql:
mysql -h Ö÷»úµØÖ· -u Óû§Ãû £­p
2.Í˳ömysql:exit
3. ÐÞ¸ÄÃÜÂë:
mysqlbinmysqladmin -uroot -p(oldpassword) password newpassword
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Ìí¼ÓÒ»¸öÓû§test1 ÃÜÂëΪABC£»ÈÃËû¿ÉÒÔÔÚÈκÎÖ÷»úÉϵǼ,²¢¶ÔËùÓÐÊý¾Ý¿âÓвéѯ¡¢²åÈë¡¢Ð޸ġ¢É¾³ýµÄȨÏÞ¡£Ê×ÏÈÓÃÒÔrootÓû§Á¬Èë
mysql,È»ºó¼üÈëÒÔÏÂÃü ......
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