MySQL5.5.21学习教程之一

     最近做项目需要MySQL，顺便捡起好久没弄的数据库了！可能要写一个系列关于MYSQL的学习笔记，那不来与大家共享！

     说到安装数据库，可真的够让人着急的！自己的系统是Windows8，安装了一圈server却没有找到最好的，功夫不负有心人。找到了mysql-5.5.21-winx64.msi。终于成功了！

      具体的安装细节请参考博客：学习数据库在win8上安装！！

show databases;
show engines;
show engines \G
show variables like 'have%';
+----------------------+----------+
| Variable_name        | Value    |
+----------------------+----------+
| have_compress        | YES      |
| have_crypt           | NO       |
| have_csv             | YES      |
| have_dynamic_loading | YES      |
| have_geometry        | YES      |
| have_innodb          | YES      |
| have_ndbcluster      | NO       |
| have_openssl         | DISABLED |
| have_partitioning    | YES      |
| have_profiling       | YES      |
| have_query_cache     | YES      |
| have_rtree_keys      | YES      |
| have_ssl             | DISABLED |
| have_symlink         | YES      |
+----------------------+----------+

show variables like 'storgae_engine%';

[mysqld]
# The TCP/IP Port the MySQL Server will listen on
port=3306

#Path to installation directory. All paths are usually resolved relative to this.
basedir="C:/Program Files/MySQL/MySQL Server 5.5/"

#Path to the database root
datadir="C:/ProgramData/MySQL/MySQL Server 5.5/Data/"

# The default character set that will be used when a new schema or table is
# created and no character set is defined
character-set-server=utf8

# The default storage engine that will be used when create new tables when
default-storage-engine=INNODB


help contents;
help Data Types;

e.g.
help TIME;

Name: 'TIME'
Description:
TIME

A time. The range is '-838:59:59' to '838:59:59'. MySQL displays TIME
values in 'HH:MM:SS' format, but permits assignment of values to TIME
columns using either strings or numbers.

URL: http://dev.mysql.com/doc/refman/5.5/en/date-and-time-type-overview.html

use test;
create TABLE f_test(a FLOAT(38,30),b DECIMAL(38,30));
INSERT INTO f_test VALUES (12443.43534534543,343243.2343546534636401);
select * from f_test \G
*************************** 1. row ***************************
a: 12443.435546875000000000000000000000
b: 343243.234354653463640100000000000000
1 row in set (0.00 sec)


create TABLE int_test(num INTEGER);
INSERT INTo int_test VALUES (0),(-1),(-1.1),(1.1),(1009888);
select * from int_test \G
*************************** 1. row ***************************
num: 0
*************************** 2. row ***************************
num: -1
*************************** 3. row ***************************
num: -1
*************************** 4. row ***************************
num: 1
*************************** 5. row ***************************
num: 1009888
5 rows in set (0.00 sec)


create TABLE bit_test(id BIT(8));
#添加的第一个数字为十进制的数字，第二个数字为二进制的数据
insert into bit_test values (11),(b'11');
select id+0 from bit_test \G
*************************** 1. row ***************************
id+0: 11
*************************** 2. row ***************************
id+0: 3
2 rows in set (0.00 sec)


select BIN(id+0) from bit_test \G
*************************** 1. row ***************************
BIN(id+0): 1011
*************************** 2. row ***************************
BIN(id+0): 11
2 rows in set (0.28 sec)


#时间日期的插入学习
create table date_test(f_date DATE,f_datetime DATETIME,f_timestamp TIMESTAMP,f_time TIME,f_year YEAR);
select CURDATE();
+------------+
| CURDATE()  |
+------------+
| 2015-01-14 |
+------------+
select CURDATE(),NOW(),NOW(),time(NOW()),year(NOW()) \G
*************************** 1. row ***************************
  CURDATE(): 2015-01-14
      NOW(): 2015-01-14 19:39:56
      NOW(): 2015-01-14 19:39:56
time(NOW()): 19:39:56
year(NOW()): 2015
1 row in set (0.00 sec)



insert into date_test values (CURDATE(),NOW(),NOW(),time(NOW()),year(NOW()));
select * from date_test \G
*************************** 1. row ***************************
     f_date: 2015-01-14
 f_datetime: 2015-01-14 19:41:07
f_timestamp: 2015-01-14 19:41:07
     f_time: 19:41:07
     f_year: 2015
1 row in set (0.00 sec)


create TABLE user(id INTEGER,name VARCHAR(20));
insert into user values (1,'bob'),(2,'petter');
select * from user;
+------+--------+
| id   | name   |
+------+--------+
|    1 | bob    |
|    2 | petter |
+------+--------+


show tables;
+----------------+
| Tables_in_test |
+----------------+
| bit_test       |
| date_test      |
| f_test         |
| int_table      |
| int_test       |
| user           |
+----------------+