用PHP和MYSQL建立计数器过程详解

  运行MYSQL.EXE

  mysql> create database counter;

  Query OK, 1 row affected (0.10 sec)

  mysql> use counter;

  Database changed

  mysql> create table tl(id integer(2),count integer(5));

  Query OK, 0 rows affected (0.21 sec)

  mysql> show columns from tl;

  +-------+--------+------+-----+---------+-------+

  | Field | Type   | Null | Key | Default | Extra |

  +-------+--------+------+-----+---------+-------+

  | id    | int(2) | YES  |     | NULL    |       |

  | count | int(5) | YES  |     | NULL    |       |

  +-------+--------+------+-----+---------+-------+

  2 rows in set (0.05 sec)

  mysql> select * from tl;

  Empty set (0.08 sec)

  mysql> insert into tl(id,count) values(1,1);

  Query OK, 1 row affected (0.02 sec)

  mysql> select * from tl;

  +------+-------+

  | id   | count |

  +------+-------+

  |    1 |     1 |

  +------+-------+

  1 row in set (0.03 sec)

  下面编写HTML文件内容:

  <html>

  <body>

  <?php

  $myvar = "来访人数:";

  echo $myvar;

  ?>

  <?php

  mysql_connect() or die("there are problems to connect to mysql!");

  $query="select * from tl";

  $result=mysql_db_query("counter",$query);

  if($result){

  $r=mysql_fetch_array($result);

  $counter=$r["count"];

  $counter=$counter+1;

  echo $counter;

  $query="update tl set count='$counter' where id=1";

  $result=mysql_db_query("counter",$query);

  mysql_close();

  }

  ?>

  </body>

  </html>