PHP-MySQL基本操作(转载)
日期:2022-02-11
// 1.防止页面中文乱码
header("content-type:text/html;charset=utf-8");
// 链接数据库
@$conn = new mysqli('localhost', 'root', '');
echo $conn == true ? '数据库连接成功' : '数据库连接失败';
// 2.连接到MySQL后设置字符集(防止存入中文乱码)
mysqli_set_charset($conn, 'utf8');
// 创建数据库
$createDatabaseSql = "create database ProsperLee01 charset utf8";
// 删除数据库
$dropDatabaseSql = "drop database ProsperLee01";
// 查询数据库
$showDatabaseSql = "show databases";
// 查询创建的数据库信息
$showCreateDatabaseSql = "show create database ProsperLee01";
// 修改数据库(不能修改数据库的名字,只能修改字符集和校对集)语法:alter database 数据库 character set=新的字符集 collate=新的校对集
$alterDatabaseSql1 = "alter database ProsperLee01 character set=gbk collate=gbk_Chinese_ci";
$alterDatabaseSql2 = "alter database ProsperLee01 charset=utf8 collate=utf8_general_ci";
// 查询字符集
$showCharsetSql = "show charset";
// 查询校对集
$showCollationSql = "show collation";
// 使用数据库
$useDatabaseSql = "use ProsperLee01";
// 创建数据表 语法 CREATE TABLE 库名 表名 (字段名 字段类型 字段选项, 字段名 字段类型 字段选项···) 表选项; (表选项:表字符集(charset=utf8)和数据引擎(engine=引擎))
$createTableSql =<<
CREATE TABLE `prosperlee01`.`Lee01` (
`name` varchar(20) DEFAULT '小明同学' NOT NULL COMMENT '姓名',
`sex` varchar(5) NULL COMMENT '性别',
`age` int(2) NULL COMMENT '年龄',
`index` int NOT NULL AUTO_INCREMENT COMMENT '序号',
`id` varchar(8) NOT NULL COMMENT 'id',
PRIMARY KEY (`index`, `id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
sss;
// 查询数据表
$showTablesSql = "show tables";
// 查看数据表结构
$descTableSql = "desc lee01";
// 查询创建的数据表
$showCreateTableSql = "show create table Lee01";
// 修改表名 alter table 旧表名 rename [to] 新表名
$alterTableNameSql = "alter table lee01 rename to newlee01";
// 添加新字段
$alterTableAddFieldSql = "alter table lee01 add realname varchar(50) not null default '用户名' comment '真实姓名'";
// 删除字段 alter table 表名 drop column 字段名
$alterTableDropFieldSql = "alter table lee01 drop column phone";
// 修改表的字段类型 ALTER TABLE 表名 MODIFY COLUMN 字段名 字段类型定义;
$alterTableModifyFieldSql = "ALTER TABLE lee01 MODIFY COLUMN id VARCHAR(32)";
// 修改表的字段名(修改后原始字段存的值不会变,新存入的值不填写变成默认值) alter table 表名 change 原字段名 新字段名 字段的类型
$alterTableChangeFieldSql = "ALTER TABLE lee01 change realname phone VARCHAR(11) default '01234567890' comment '电话号'";
// 插入数据 INSERT INTO table_name (列1, 列2,...) VALUES (值1, 值2,....)
$insertIntoDataSql1 = "INSERT INTO Lee01 (`sex`,`age`,`id`) VALUES ('女',20,'88888888')";
$insertIntoDataSql2 = "INSERT INTO Lee01 (`name`,`sex`,`age`,`id`) VALUES ('Lee','女',20,'66666666')";
$insertIntoDataSql = <<
INSERT INTO Lee01 ( `name`, `sex`, `age`, `id` )
VALUES
( '张三', '女', 16, '12345678' ),
( '李四', '男', 18, '87654321' ),
( '王五', '女', 20, '22222222' ),
( '赵六', '女', 21, '11111111' ),
( '八爷', '男', 26, '14725836' ),
( '九少', '男', 16, '66666666' )
sss;
// 查询语句
$selectDataSql1 = "select * from lee01";
$selectDataSql2 = "select * from lee01 where sex = '女' and age = '20'";
$selectDataSql3 = "select * from lee01 where age = '20' or age = '16'";
$selectDataSql4 = "select * from lee01 where not age = '20'";
$selectDataSql5 = "select name,age from lee01 where age = '20' or age = '16'";
// in 查询指定index (无则跳过)
$selectDataSql6 = "select name,age from lee01 where `index` in (1,2,4,6)";
// between 语法:select 查询字段 from 表名 where 字段 between 最小值 and 最大值;
$selectDataSql7 = "select name from lee01 where `index` between 2 and 5";
// 查询数据量(启用别名)
$selectDataSql8 = "select count(`index`) as count from lee01";
// like 模糊查询(注:直接写字符,严格匹配)%匹配任何字符
$selectDataSql9 = "select * from lee01 where name like '%三%'";
// group by (只能查看分组后的数量,而不能查看分组后的信息)
$selectDataSql10 = "select count(sex),sex from lee01 group by sex";
// 查询性别数量大于2个的性别的数量
$selectDataSql11 = "select count(sex) as sexnum,sex from lee01 group by sex having sexnum>2";
// 查询正序(asc)倒序(desc)
$selectDataSql12 = "select * from lee01 order by id asc";
// 分页查询 (limit 下标,查询数量)
$selectDataSql13 = "select * from lee01 order by `index` asc limit 0,2";
$selectDataSql14 = "select * from lee01 order by `index` asc limit 2,2";
$selectDataSql15 = "select * from lee01 order by `index` asc limit 4,2";
// 删除数据表
$dropTableSql = "drop table lee01";
// 清空数据表(同时删除自增字段的定义)
$truncateTableSql1 = "truncate table lee01";
// 清空数据表(删除表中的所有行,一行一行的删)(delete 保留原有自增字段,再次创建不占用删除字段)
$deleteTableSql1 = "delete from lee01";
// 按条件删除 delete from 表名 [where条件] [order排序] [limit限定](删除范围数据可能会用到order、limit)
$deleteTableSql2 = "delete from lee01 where phone = '用户名'";
// 修改数据(无条件全改)
$updateSetSql = "update lee01 set name = 'ProsperLee',age=23 where id = '87654321'";
// 使用数据库
mysqli_select_db($conn, 'ProsperLee01'); // 使用数据库
// 3.设置通信编码
mysqli_query($conn, "set names utf8");
// 执行sql语句
$result = mysqli_query($conn, $selectDataSql1);
var_dump($result);
/**
* fetch_assoc() 每次拿1条数据
* fetch_all() 拿出全部数据
*/
$showData = $result->fetch_all();
var_dump($showData);
// 关闭数据库
mysqli_close($conn);
header("content-type:text/html;charset=utf-8");
// 链接数据库
@$conn = new mysqli('localhost', 'root', '');
echo $conn == true ? '数据库连接成功' : '数据库连接失败';
// 2.连接到MySQL后设置字符集(防止存入中文乱码)
mysqli_set_charset($conn, 'utf8');
// 创建数据库
$createDatabaseSql = "create database ProsperLee01 charset utf8";
// 删除数据库
$dropDatabaseSql = "drop database ProsperLee01";
// 查询数据库
$showDatabaseSql = "show databases";
// 查询创建的数据库信息
$showCreateDatabaseSql = "show create database ProsperLee01";
// 修改数据库(不能修改数据库的名字,只能修改字符集和校对集)语法:alter database 数据库 character set=新的字符集 collate=新的校对集
$alterDatabaseSql1 = "alter database ProsperLee01 character set=gbk collate=gbk_Chinese_ci";
$alterDatabaseSql2 = "alter database ProsperLee01 charset=utf8 collate=utf8_general_ci";
// 查询字符集
$showCharsetSql = "show charset";
// 查询校对集
$showCollationSql = "show collation";
// 使用数据库
$useDatabaseSql = "use ProsperLee01";
// 创建数据表 语法 CREATE TABLE 库名 表名 (字段名 字段类型 字段选项, 字段名 字段类型 字段选项···) 表选项; (表选项:表字符集(charset=utf8)和数据引擎(engine=引擎))
$createTableSql =<<
CREATE TABLE `prosperlee01`.`Lee01` (
`name` varchar(20) DEFAULT '小明同学' NOT NULL COMMENT '姓名',
`sex` varchar(5) NULL COMMENT '性别',
`age` int(2) NULL COMMENT '年龄',
`index` int NOT NULL AUTO_INCREMENT COMMENT '序号',
`id` varchar(8) NOT NULL COMMENT 'id',
PRIMARY KEY (`index`, `id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
sss;
// 查询数据表
$showTablesSql = "show tables";
// 查看数据表结构
$descTableSql = "desc lee01";
// 查询创建的数据表
$showCreateTableSql = "show create table Lee01";
// 修改表名 alter table 旧表名 rename [to] 新表名
$alterTableNameSql = "alter table lee01 rename to newlee01";
// 添加新字段
$alterTableAddFieldSql = "alter table lee01 add realname varchar(50) not null default '用户名' comment '真实姓名'";
// 删除字段 alter table 表名 drop column 字段名
$alterTableDropFieldSql = "alter table lee01 drop column phone";
// 修改表的字段类型 ALTER TABLE 表名 MODIFY COLUMN 字段名 字段类型定义;
$alterTableModifyFieldSql = "ALTER TABLE lee01 MODIFY COLUMN id VARCHAR(32)";
// 修改表的字段名(修改后原始字段存的值不会变,新存入的值不填写变成默认值) alter table 表名 change 原字段名 新字段名 字段的类型
$alterTableChangeFieldSql = "ALTER TABLE lee01 change realname phone VARCHAR(11) default '01234567890' comment '电话号'";
// 插入数据 INSERT INTO table_name (列1, 列2,...) VALUES (值1, 值2,....)
$insertIntoDataSql1 = "INSERT INTO Lee01 (`sex`,`age`,`id`) VALUES ('女',20,'88888888')";
$insertIntoDataSql2 = "INSERT INTO Lee01 (`name`,`sex`,`age`,`id`) VALUES ('Lee','女',20,'66666666')";
$insertIntoDataSql = <<
INSERT INTO Lee01 ( `name`, `sex`, `age`, `id` )
VALUES
( '张三', '女', 16, '12345678' ),
( '李四', '男', 18, '87654321' ),
( '王五', '女', 20, '22222222' ),
( '赵六', '女', 21, '11111111' ),
( '八爷', '男', 26, '14725836' ),
( '九少', '男', 16, '66666666' )
sss;
// 查询语句
$selectDataSql1 = "select * from lee01";
$selectDataSql2 = "select * from lee01 where sex = '女' and age = '20'";
$selectDataSql3 = "select * from lee01 where age = '20' or age = '16'";
$selectDataSql4 = "select * from lee01 where not age = '20'";
$selectDataSql5 = "select name,age from lee01 where age = '20' or age = '16'";
// in 查询指定index (无则跳过)
$selectDataSql6 = "select name,age from lee01 where `index` in (1,2,4,6)";
// between 语法:select 查询字段 from 表名 where 字段 between 最小值 and 最大值;
$selectDataSql7 = "select name from lee01 where `index` between 2 and 5";
// 查询数据量(启用别名)
$selectDataSql8 = "select count(`index`) as count from lee01";
// like 模糊查询(注:直接写字符,严格匹配)%匹配任何字符
$selectDataSql9 = "select * from lee01 where name like '%三%'";
// group by (只能查看分组后的数量,而不能查看分组后的信息)
$selectDataSql10 = "select count(sex),sex from lee01 group by sex";
// 查询性别数量大于2个的性别的数量
$selectDataSql11 = "select count(sex) as sexnum,sex from lee01 group by sex having sexnum>2";
// 查询正序(asc)倒序(desc)
$selectDataSql12 = "select * from lee01 order by id asc";
// 分页查询 (limit 下标,查询数量)
$selectDataSql13 = "select * from lee01 order by `index` asc limit 0,2";
$selectDataSql14 = "select * from lee01 order by `index` asc limit 2,2";
$selectDataSql15 = "select * from lee01 order by `index` asc limit 4,2";
// 删除数据表
$dropTableSql = "drop table lee01";
// 清空数据表(同时删除自增字段的定义)
$truncateTableSql1 = "truncate table lee01";
// 清空数据表(删除表中的所有行,一行一行的删)(delete 保留原有自增字段,再次创建不占用删除字段)
$deleteTableSql1 = "delete from lee01";
// 按条件删除 delete from 表名 [where条件] [order排序] [limit限定](删除范围数据可能会用到order、limit)
$deleteTableSql2 = "delete from lee01 where phone = '用户名'";
// 修改数据(无条件全改)
$updateSetSql = "update lee01 set name = 'ProsperLee',age=23 where id = '87654321'";
// 使用数据库
mysqli_select_db($conn, 'ProsperLee01'); // 使用数据库
// 3.设置通信编码
mysqli_query($conn, "set names utf8");
// 执行sql语句
$result = mysqli_query($conn, $selectDataSql1);
var_dump($result);
/**
* fetch_assoc() 每次拿1条数据
* fetch_all() 拿出全部数据
*/
$showData = $result->fetch_all();
var_dump($showData);
// 关闭数据库
mysqli_close($conn);