随笔分类 - MySQL
摘要：mysql> create table student(age int(4), name varchar(20));Query OK, 0 rows affected (0.09 sec)mysql> insert into student values(21, 'Jack'), (23, 'Rose'), (35, 'Ann'), (56, 'Mike');Query OK, 4 rows affected (0.06 sec)Records: 4 Duplicates: 0 Warnings: 0mysql>
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摘要：（参考）http://www.jb51.net/article/36356.htm（1）VERSION()返回数据库版本号mysql> select VERSION();+-----------+| VERSION() |+-----------+| 5.5.8-log |+-----------+1 row in set (0.00 sec)（2）CONNECTION_ID()返回数据库的连接次数mysql> select CONNECTION_ID();+-----------------+| CONNECTION_ID() |+-----------------+| 40 |
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摘要：（转载）http://www.cnblogs.com/cocos/archive/2011/05/06/2039469.html对于针对字符串位置的操作，第一个位置被标记为1。ASCII(str)返回字符串str的最左面字符的ASCII代码值。如果str是空字符串，返回0。如果str是NULL，返回NULL。mysql> select ASCII('2'); -> 50mysql> select ASCII(2); -> 50mysql> select ASCII('dx'); -> 100也可参见ORD()函数。ORD(st
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摘要：# BIN(N）返回二进制值N的一个字符串表示mysql> select bin(123);+----------+| bin(123) |+----------+| 1111011 |+----------+1 row in set (0.00 sec)# OCT(N）返回八进制值N的一个字符串表示mysql> select oct(123);+----------+| oct(123) |+----------+| 173 |+----------+1 row in set (0.00 sec)# HEX(N）返回十六进制值N的一个字符串表示mysql> select h
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摘要：（1）delete form 表名，清空表的内容mysql> use test;Database changedmysql> create table teacher(age int(3));Query OK, 0 rows affected (0.07 sec)mysql> insert into teacher values(111), (45), (23), (34);Query OK, 4 rows affected (0.04 sec)Records: 4 Duplicates: 0 Warnings: 0mysql> select * from teache
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摘要：mysql> use test;Database changedmysql> create table teacher(score decimal(6, 2));Query OK, 0 rows affected (0.04 sec)mysql> insert into teacher values(34.35464), (23534523.45434), ('3223.3557');Query OK, 3 rows affected, 3 warnings (0.04 sec)Records: 3 Duplicates: 0 Warnings: 3mysql
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摘要：mysql> use test;Database changedmysql> create table teacher(birthday DATE);Query OK, 0 rows affected (0.24 sec)mysql> desc teacher;+----------+------+------+-----+---------+-------+| Field | Type | Null | Key | Default | Extra |+----------+------+------+-----+---------+-------+| birthday |
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摘要：mysql> select * from student;+------+------+-----------+| age | name | address |+------+------+-----------+| 12 | Jack | BeiJing || 19 | Mike | TianJin || 21 | Rose | ZhuHai || 23 | Ann | ShangHai || 27 | Alis | ShenZhen || 55 | Make | GuangZhou |+------+------+-----------+6 rows in set (0.00 sec
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摘要：mysql> select * from student;+------+------+-----------+| age | name | address |+------+------+-----------+| 12 | Jack | BeiJing || 19 | Mike | TianJin || 21 | Rose | ZhuHai || 23 | Ann | ShangHai || 27 | Alis | ShenZhen || 55 | Make | GuangZhou |+------+------+-----------+6 rows in set (0.00 sec
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摘要：mysql> select * from student;+------+------+-----------+| age | name | address |+------+------+-----------+| 12 | Jack | BeiJing || 19 | Mike | TianJin || 21 | Rose | ZhuHai || 23 | Ann | ShangHai || 27 | Alis | ShenZhen || 55 | Make | GuangZhou |+------+------+-----------+6 rows in set (0.00 sec
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摘要：mysql> use test;Database changedmysql> create table student(age int(4), name varchar(20), address varchar(20));Query OK, 0 rows affected (0.22 sec)mysql> insert into student values(12, 'Jack', 'BeiJing'), (19, 'Mike', 'TianJin'), (21, 'Rose', 'Zhu
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摘要：（转载）http://www.cnblogs.com/xiongjiaji/articles/2476492.htmlBLOB介绍 BLOB (binary large object)，二进制大对象，是一个可以存储二进制文件的容器。在计算机中，BLOB常常是数据库中用来存储二进制文件的字段类型。BLOB是一个大文件，典型的BLOB是一张图片或一个声音文件，由于它们的尺寸，必须使用特殊的方式来处理（例如：上传、下载或者存放到一个数据库）。根据Eric Raymond的说法，处理BLOB的主要思想就是让文件处理器（如数据库管理器）不去理会文件是什么，而是关心如何去处理它。但也有专家强调，这种处理大
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摘要：（转载）http://blog.csdn.net/wangman_512/article/details/6761512今天复习了MySQL，说实话从高中我学的最有兴趣的一门就是数据库，所见今天听的很轻松。今天主要复习了MySQL的一些简单语句，可总结：MySQL的一些基础语句：行是记录列是字段创建库CREATEDATABASE[IFNOTEXISTS]数据库名[参数[参数][参数]...];参数:CHARACTERSET码表名COLLATE校对规则名,详见文档10.10.1显示库SHOWDATABASES;显示数据库创建语句SHOWCREATEDATABASE数据库名;修改库ALTERDAT
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摘要：语法：UPDATE 表名 SET 列名=值 [WHERE 条件语句];mysql> SELECT * FROM student_info;+------+---------+| age | name |+------+---------+| 12 | Lili || 27 | Jack || 25 | Rose || 25 | Ann || 26 | Mark || 68 | Bill || 16 | James || 20 | Fred || 8 | Gary || 22 | Martin...
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摘要：语法：SELECT COUNT(*) | COUNT(列名) FROM 表名 [WHERE 条件语句]mysql> select * from student_info;+------+---------+| age | name |+------+---------+| 12 | Lili || 27 | Jack || 25 | Rose || 25 | Ann || 26 | Mark || 68 | Bill || 16 | James || 20 | Fred || 8 | Gary ...
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摘要：（1）修改表名格式：RANAME TABLE 原表名 TO 新表名;mysql> RENAME TABLE student TO student_info;Query OK, 0 rows affected (0.00 sec)mysql> show tables;+----------------+| Tables_in_test |+----------------+| student_info |+----------------+1 row in set (0.00 sec)mysql>（2）添加列格式：ALTER TABLE 表名ADD COLUMN列名 类型名;m
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摘要：（1）use命令mysql> use test; # 打开一个已存在的数据库（2）system命令执行系统命令mysql> system clear; # 执行Linux的清屏命令，非常实用的一个命令（3）quit命令或exit命令mysql> quit # quit和exit命令都是退出MySQLBye（4）prompt命令改变MySQL的提示方式mysql> prompt mysql#PROMPT set to 'mysql#'mysql#（5）status命令获得当前数据库服务器的状态mysql> statusmysql>status;
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摘要：mysql> select * from student;+------+------+| Id | name |+------+------+| 12 | Lili || 34 | Jack || 57 | Old || 26 | Rose || 26 | Ann |+------+------+5 rows in set (0.00 sec)# 可以看到使用&&“或操作符”mysql> delete from student where Id=26 && name='Ann';Query OK, 1 row affected (0
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摘要：mysql> use test;Database changedmysql> select * from student;+------+------+| Id | name |+------+------+| 29 | Mike || 12 | Lili |+------+------+2 rows in set (0.00 sec)mysql> quitBye[root@localhost ~]#源文件mysql.c如下： 1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <strin
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摘要：（转载）http://www.cnblogs.com/ymy124/archive/2012/04/19/2457730.html//MYSQL_RES保存查询结构MYSQL_RES*result_=NULL;interror_code=0;//保存错误码charerror_info[1024]='\0';//保存错误信息//对mysql数据库进行查询操作:charquery_sql[1024]="select*fromdb_name.table_name"; //构建查询sql语句if(result_!=NULL)//防止之前已经被使用过（所有的使用，在使
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