语法
# CREATE TABLE table_name (column_name column_type);
CREATE TABLE IF NOT EXISTS `runoob_tbl`(
`runoob_id` INT UNSIGNED AUTO_INCREMENT,
`runoob_title` VARCHAR(100) NOT NULL,
`runoob_author` VARCHAR(40) NOT NULL,
`submission_date` DATE,
PRIMARY KEY ( `runoob_id` )
)ENGINE=InnoDB DEFAULT CHARSET=utf8;
实例解析:
通过命令提示符创建表
实例
root@host# mysql -u root -p
Enter password:*******
mysql> use RUNOOB;
Database changed
mysql> CREATE TABLE runoob_tbl(
-> runoob_id INT NOT NULL AUTO_INCREMENT,
-> runoob_title VARCHAR(100) NOT NULL,
-> runoob_author VARCHAR(40) NOT NULL,
-> submission_date DATE,
-> PRIMARY KEY ( runoob_id )
-> )ENGINE=InnoDB DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.16 sec)
mysql>
使用PHP脚本创建数据表
语法
# mysqli_query(connection,query,resultmode);
参数 | 描述 |
---|---|
connection | 必需。规定要使用的 MySQL 连接。 |
query | 必需,规定查询字符串。 |
resultmode | 可选。一个常量。可以是下列值中的任意一个: MYSQLI_USE_RESULT(如果需要检索大量数据,请使用这个) MYSQLI_STORE_RESULT(默认) |
实例
以下实例使用了PHP脚本来创建数据表:
<?php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
die('连接失败: ' . mysqli_error($conn));
}
echo '连接成功<br />';
$sql = "CREATE TABLE runoob_tbl( ".
"runoob_id INT NOT NULL AUTO_INCREMENT, ".
"runoob_title VARCHAR(100) NOT NULL, ".
"runoob_author VARCHAR(40) NOT NULL, ".
"submission_date DATE, ".
"PRIMARY KEY ( runoob_id ))ENGINE=InnoDB DEFAULT CHARSET=utf8; ";
mysqli_select_db( $conn, 'RUNOOB' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
die('数据表创建失败: ' . mysqli_error($conn));
}
echo "数据表创建成功\n";
mysqli_close($conn);
?>
执行成功后,就可以通过命令行查看表结构:
语法
# DROP TABLE table_name ;
在命令提示窗口中删除数据表:
实例
root@host# mysql -u root -p
Enter password:*******
mysql> use RUNOOB;
Database changed
mysql> DROP TABLE runoob_tbl
Query OK, 0 rows affected (0.8 sec)
mysql>
使用PHP脚本删除数据表
语法
# mysqli_query(connection,query,resultmode);
参数 | 描述 |
---|---|
connection | 必需。规定要使用的 MySQL 连接。 |
query | 必需,规定查询字符串。 |
resultmode | 可选。一个常量。可以是下列值中的任意一个: MYSQLI_USE_RESULT(如果需要检索大量数据,请使用这个) MYSQLI_STORE_RESULT(默认) |
实例
<?php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
die('连接失败: ' . mysqli_error($conn));
}
echo '连接成功<br />';
$sql = "DROP TABLE runoob_tbl"; mysqli_select_db( $conn, 'RUNOOB' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
die('数据表删除失败: ' . mysqli_error($conn));
}
echo "数据表删除成功\n";
mysqli_close($conn);
?>
# mysql> show tables;
# Empty set (0.01 sec)
语法
INSERT INTO table_name ( field1, field2,...fieldN )
VALUES
( value1, value2,...valueN );
通过命令提示窗口插入数据
实例
root@host# mysql -u root -p password;
Enter password:*******
mysql> use RUNOOB;
Database changed
mysql> INSERT INTO runoob_tbl
-> (runoob_title, runoob_author, submission_date)
-> VALUES
-> ("学习 PHP", "前端", NOW());
Query OK, 1 rows affected, 1 warnings (0.01 sec)
mysql> INSERT INTO runoob_tbl
-> (runoob_title, runoob_author, submission_date)
-> VALUES
-> ("学习 MySQL", "Python", NOW());
Query OK, 1 rows affected, 1 warnings (0.01 sec)
mysql> INSERT INTO runoob_tbl
-> (runoob_title, runoob_author, submission_date)
-> VALUES
-> ("JAVA 教程", "RUNOOB.COM", '2016-05-06');
Query OK, 1 rows affected (0.00 sec)
mysql>
读取数据表:
# select * from runoob_tbl;
使用PHP脚本插入数据
语法
# mysqli_query(connection,query,resultmode);
参数 | 描述 |
---|---|
connection | 必需。规定要使用的 MySQL 连接。 |
query | 必需,规定查询字符串。 |
resultmode | 可选。一个常量。可以是下列值中的任意一个: MYSQLI_USE_RESULT(如果需要检索大量数据,请使用这个) MYSQLI_STORE_RESULT(默认) |
实例
<?php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
die('连接失败: ' . mysqli_error($conn));
}
echo '连接成功<br />';
// 设置编码,防止中文乱码
mysqli_query($conn , "set names utf8");
$runoob_title = '学习 Python';
$runoob_author = 'RUNOOB.COM';
$submission_date = '2016-03-06';
$sql = "INSERT INTO runoob_tbl ".
"(runoob_title,runoob_author, submission_date) ".
"VALUES ".
"('$runoob_title','$runoob_author','$submission_date')"; mysqli_select_db( $conn, 'RUNOOB' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
die('无法插入数据: ' . mysqli_error($conn));
}
echo "数据插入成功\n";
mysqli_close($conn);
?>
读取数据表:
# select * from runoob_tbl;
语法
以下为在MySQL数据库中查询数据通用的 SELECT 语法:
# SELECT column_name,column_name
# FROM table_name
# [WHERE Clause]
# [LIMIT N][ OFFSET M]
最基本查询语句
mysql> select * from student limit 2; #仅查看student表中前两行数据
mysql> select * from student limit 5 offset 3; #从第三行开始查询,并且只显示5行数据
GROUP BY 语句:指定以什么分组(比如可以统计出有多少同名数据)
mysql> select name,count(*) from student group by name;
mysql> select coalesce(name,"Total age"),sum(age) from student group by name with rollup;
修改(update)
mysql> update student set name="lisi",age=22 where id=1; #将表中id=1的条目改成name=lisi,age=22
mysql> update student set name="lisi",age=22 where id>4; #上面仅仅修改一条,这里修改id>4的所有
删除(delete)
mysql> delete from student where name="zhangsan"; #删除student表中所有name=“zhangsan”
语法
SELECT field1, field2,...fieldN FROM table_name1, table_name2...
[WHERE condition1 [AND [OR]] condition2.....
以下为操作符列表,可用于 WHERE 子句中。
操作符 | 描述 | 实例 |
---|---|---|
= | 等号,检测两个值是否相等,如果相等返回true | (A = B) 返回false。 |
<>, != | 不等于,检测两个值是否相等,如果不相等返回true | (A != B) 返回 true。 |
> | 大于号,检测左边的值是否大于右边的值, 如果左边的值大于右边的值返回true | (A > B) 返回false。 |
< | 小于号,检测左边的值是否小于右边的值, 如果左边的值小于右边的值返回true | (A < B) 返回 true。 |
>= | 大于等于号,检测左边的值是否大于或等于右边的值, 如果左边的值大于或等于右边的值返回true | (A >= B) 返回false。 |
<= | 小于等于号,检测左边的值是否小于或等于右边的值, 如果左边的值小于或等于右边的值返回true | (A <= B) 返回 true。 |
where; like; order by;使用
mysql> select * from student where id >3 and age >103;
mysql> select * from student where register_data like "2016-06%"; #查询所有在2016-06这一条新建的条目
mysql> select * from student order by id desc; #按主键降续
mysql> select * from student order by id asc; #按主键升续排序(默认升续)
mysql> select * from student where name like binary "%si" order by id desc;
#查找名字以“si”结尾的所有条目,并且按照id降续排列
语法
# UPDATE table_name SET field1=new-value1, field2=new-value2
# [WHERE Clause]
通过命令提示符更新数据
实例
SQL UPDATE 语句:
mysql> UPDATE runoob_tbl SET runoob_title='学习 C++' WHERE runoob_id=3;
Query OK, 1 rows affected (0.01 sec)
mysql> SELECT * from runoob_tbl WHERE runoob_id=3;
+-----------+--------------+---------------+-----------------+
| runoob_id | runoob_title | runoob_author | submission_date |
+-----------+--------------+---------------+-----------------+
| 3 | 学习 C++ |RUNOOB.COM | 2016-05-06 |
+-----------+--------------+---------------+-----------------+
1 rows in set (0.01 sec)
使用PHP脚本更新数据
实例
<?php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
die('连接失败: ' . mysqli_error($conn)); }
// 设置编码,防止中文乱码
mysqli_query($conn , "set names utf8");
$sql = 'UPDATE runoob_tbl
SET runoob_title="学习 Python"
WHERE runoob_id=3';
mysqli_select_db( $conn, 'RUNOOB' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
die('无法更新数据: ' . mysqli_error($conn));
}
echo '数据更新成功!';
mysqli_close($conn);
?>
语法
# DELETE FROM table_name [WHERE Clause]
从命令行中删除数据
实例
DELETE 语句:
mysql> use RUNOOB;
Database changed mysql> DELETE FROM runoob_tbl WHERE runoob_id=3;
Query OK, 1 row affected (0.23 sec)
使用 PHP 脚本删除数据
实例
<?php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
die('连接失败: ' . mysqli_error($conn));
}
// 设置编码,防止中文乱码
mysqli_query($conn , "set names utf8");
$sql = 'DELETE FROM runoob_tbl WHERE runoob_id=3'; mysqli_select_db( $conn, 'RUNOOB' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
die('无法删除数据: ' . mysqli_error($conn));
}
echo '数据删除成功!';
mysqli_close($conn);
?>
语法
SELECT field1, field2,...fieldN
FROM table_name
WHERE field1 LIKE condition1 [AND [OR]] filed2 = 'somevalue'
在命令提示符中使用 LIKE 子句
实例
SQL LIKE 语句:
mysql> use RUNOOB;
Database changed
mysql> SELECT * from runoob_tbl WHERE runoob_author LIKE '%COM';
+-----------+---------------+---------------+-----------------+
| runoob_id | runoob_title | runoob_author | submission_date |
+-----------+---------------+---------------+-----------------+
| 3 | 学习 Java | RUNOOB.COM | 2015-05-01 |
| 4 | 学习 Python | RUNOOB.COM | 2016-03-06 |
+-----------+---------------+---------------+-----------------+
2 rows in set (0.01 sec)
示例
'%a' # 以a结尾的数据
'a%' # 以a开头的数据
'%a%' # 含有a的数据
'_a_' # 三位且中间字母是a的
'_a' # 两位且结尾字母是a的
'a_' # 两位且开头字母是a的
# 查询以 Python 字段开头的信息。
SELECT * FROM position WHERE name LIKE 'Python%';
# 查询包含 Python 字段的信息。
SELECT * FROM position WHERE name LIKE '%Python%';
# 查询以 Python 字段结尾的信息。
SELECT * FROM position WHERE name LIKE '%Python';
描述
语法
SELECT expression1, expression2, ... expression_n
FROM tables
[WHERE conditions]
UNION [ALL | DISTINCT]
SELECT expression1, expression2, ... expression_n
FROM tables
[WHERE conditions];
参数
演示数据库
# mysql> SELECT * FROM Websites;
+----+--------------+---------------------------+-------+---------+
| id | name | url | alexa | country |
+----+--------------+---------------------------+-------+---------+
| 1 | Google | https://www.google.cm/ | 1 | USA |
| 2 | 淘宝 | https://www.taobao.com/ | 13 | CN |
| 3 | 菜鸟教程 | http://www.runoob.com/ | 4689 | CN |
| 4 | 微博 | http://weibo.com/ | 20 | CN |
| 5 | Facebook | https://www.facebook.com/ | 3 | USA |
| 7 | stackoverflow | http://stackoverflow.com/ | 0 | IND |
+----+---------------+---------------------------+-------+--------+
# mysql> SELECT * FROM apps;
+----+------------+-------------------------+---------+
| id | app_name | url | country |
+----+------------+-------------------------+---------+
| 1 | QQ APP | http://im.qq.com/ | CN |
| 2 | 微博 APP | http://weibo.com/ | CN |
| 3 | 淘宝 APP | https://www.taobao.com/ | CN |
+----+------------+-------------------------+---------+
3 rows in set (0.00 sec)
实例
SELECT country FROM Websites
UNION
SELECT country FROM apps
ORDER BY country;
SQL UNION ALL 实例
实例
SELECT country FROM Websites
UNION ALL
SELECT country FROM apps
ORDER BY country;
带有 WHERE 的 SQL UNION ALL
实例
SELECT country, name FROM Websites
WHERE country='CN'
UNION ALL
SELECT country, app_name FROM apps
WHERE country='CN'
ORDER BY country;
以上内容是对 MySQL 数据库表操作的讲述、后续更新内容从分组开始、详细内容请听下回分解