mysql基本操作

一、基本操作

连接Mysql后，结束一条sql语句要在后面加一个分号”；“。

• 创建数据库

#在创建数据时，可以在数据库名前后加一个反引号（TAB键上的一个键），这样就可以用关键字创建一个数据库了，否则报错。
mysql> create database customer;
Query OK, 1 row affected (0.00 sec)

• 查看mysql版本

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.6.38    |
+-----------+
1 row in set (0.00 sec)

• 查看当前数据库

mysql> select database();
+------------+
| database() |
+------------+
| NULL       |
+------------+
1 row in set (0.00 sec)

• 查看当前的登录用户名

mysql> select user();
+----------------+
| user()         |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)

• 查看当前的登录用户名

mysql> select current_user();
+----------------+
| current_user() |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)

• 查看当前日期时间

mysql> select curtime(),curdate(),now();
+-----------+------------+---------------------+
| curtime() | curdate()  | now()               |
+-----------+------------+---------------------+
| 15:43:50  | 2018-01-15 | 2018-01-15 15:43:50 |
+-----------+------------+---------------------+
1 row in set (0.00 sec)

• 查看有多少数据库

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
4 rows in set (0.01 sec)

• 删除一个指定的数据库

drop database 数据库名

• 切换一个数据库为当前数据库

use 数据库名

mysql> use test
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| test       |
+------------+
1 row in set (0.00 sec)

• 查看字符集

mysql> show variables like 'char%';
+--------------------------+--------------------------+
| Variable_name            | Value                    |
+--------------------------+--------------------------+
| character_set_client     | gbk                      |
| character_set_connection | gbk                      |
| character_set_database   | latin1                   |
| character_set_filesystem | binary                   |
| character_set_results    | gbk                      |
| character_set_server     | latin1                   |
| character_set_system     | utf8                     |
| character_sets_dir       | c:\mysql\share\charsets\ |
+--------------------------+--------------------------+
8 rows in set (0.00 sec)

• 设置连接服务器及当前客户端的字符集

mysql> set names utf8;
Query OK, 0 rows affected (0.00 sec)

• 查看当前服务支持的字符集

mysql> show charset;
+----------+-----------------------------+---------------------+--------+
| Charset  | Description                 | Default collation   | Maxlen |
+----------+-----------------------------+---------------------+--------+
| big5     | Big5 Traditional Chinese    | big5_chinese_ci     |      2 |
| dec8     | DEC West European           | dec8_swedish_ci     |      1 |
| cp850    | DOS West European           | cp850_general_ci    |      1 |
| hp8      | HP West European            | hp8_english_ci      |      1 |
| koi8r    | KOI8-R Relcom Russian       | koi8r_general_ci    |      1 |
| latin1   | cp1252 West European        | latin1_swedish_ci   |      1 |
| latin2   | ISO 8859-2 Central European | latin2_general_ci   |      1 |
| swe7     | 7bit Swedish                | swe7_swedish_ci     |      1 |
| ascii    | US ASCII                    | ascii_general_ci    |      1 |
| ujis     | EUC-JP Japanese             | ujis_japanese_ci    |      3 |
| sjis     | Shift-JIS Japanese          | sjis_japanese_ci    |      2 |
| hebrew   | ISO 8859-8 Hebrew           | hebrew_general_ci   |      1 |
| tis620   | TIS620 Thai                 | tis620_thai_ci      |      1 |
| euckr    | EUC-KR Korean               | euckr_korean_ci     |      2 |
| koi8u    | KOI8-U Ukrainian            | koi8u_general_ci    |      1 |
| gb2312   | GB2312 Simplified Chinese   | gb2312_chinese_ci   |      2 |
| greek    | ISO 8859-7 Greek            | greek_general_ci    |      1 |
| cp1250   | Windows Central European    | cp1250_general_ci   |      1 |
| gbk      | GBK Simplified Chinese      | gbk_chinese_ci      |      2 |
| latin5   | ISO 8859-9 Turkish          | latin5_turkish_ci   |      1 |
| armscii8 | ARMSCII-8 Armenian          | armscii8_general_ci |      1 |
| utf8     | UTF-8 Unicode               | utf8_general_ci     |      3 |
| ucs2     | UCS-2 Unicode               | ucs2_general_ci     |      2 |
| cp866    | DOS Russian                 | cp866_general_ci    |      1 |
| keybcs2  | DOS Kamenicky Czech-Slovak  | keybcs2_general_ci  |      1 |
| macce    | Mac Central European        | macce_general_ci    |      1 |
| macroman | Mac West European           | macroman_general_ci |      1 |
| cp852    | DOS Central European        | cp852_general_ci    |      1 |
| latin7   | ISO 8859-13 Baltic          | latin7_general_ci   |      1 |
| utf8mb4  | UTF-8 Unicode               | utf8mb4_general_ci  |      4 |
| cp1251   | Windows Cyrillic            | cp1251_general_ci   |      1 |
| utf16    | UTF-16 Unicode              | utf16_general_ci    |      4 |
| utf16le  | UTF-16LE Unicode            | utf16le_general_ci  |      4 |
| cp1256   | Windows Arabic              | cp1256_general_ci   |      1 |
| cp1257   | Windows Baltic              | cp1257_general_ci   |      1 |
| utf32    | UTF-32 Unicode              | utf32_general_ci    |      4 |
| binary   | Binary pseudo charset       | binary              |      1 |
| geostd8  | GEOSTD8 Georgian            | geostd8_general_ci  |      1 |
| cp932    | SJIS for Windows Japanese   | cp932_japanese_ci   |      2 |
| eucjpms  | UJIS for Windows Japanese   | eucjpms_japanese_ci |      3 |
+----------+-----------------------------+---------------------+--------+
40 rows in set (0.02 sec)

• 查看数据库引擎

mysql> show engines;
+--------------------+---------+------------------------------------------------
----------------+--------------+------+------------+
| Engine             | Support | Comment
                | Transactions | XA   | Savepoints |
+--------------------+---------+------------------------------------------------
----------------+--------------+------+------------+
| FEDERATED          | NO      | Federated MySQL storage engine
                | NULL         | NULL | NULL       |
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables
                | NO           | NO   | NO         |
| MyISAM             | YES     | MyISAM storage engine
                | NO           | NO   | NO         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to
 it disappears) | NO           | NO   | NO         |
| CSV                | YES     | CSV storage engine
                | NO           | NO   | NO         |
| MEMORY             | YES     | Hash based, stored in memory, useful for tempor
ary tables      | NO           | NO   | NO         |
| ARCHIVE            | YES     | Archive storage engine
                | NO           | NO   | NO         |
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and f
oreign keys     | YES          | YES  | YES        |
| PERFORMANCE_SCHEMA | YES     | Performance Schema
                | NO           | NO   | NO         |
+--------------------+---------+------------------------------------------------
----------------+--------------+------+------------+
9 rows in set (0.01 sec)

• 修改数据库的字符集

mysql> alter database `db` character set utf8;
Query OK, 1 row affected (0.00 sec)