MySQL Tutorial/Introduction/Introduction

Connecting To Your Database

In order to log into MySQL we must pass information to the MySQL client program when we start it.

This is done with the following commands and syntax.

c:\mysql\bin\mysql -u <mysql_username> -p <password> <database name>

Database, table, index, column, and alias names are identifiers.

The maximum length for each type of identifier.

Identifier Maximum Length (bytes) Database 64 Table 64 Column 64 Index 64 Alias 255

Keywords may be entered in any lettercase.

The following queries are equivalent:

mysql>
mysql>
mysql> SELECT VERSION();
+---------------------+
| VERSION()           |
+---------------------+
| 5.0.41-community-nt |
+---------------------+
1 row in set (0.00 sec)
mysql> select version();
+---------------------+
| version()           |
+---------------------+
| 5.0.41-community-nt |
+---------------------+
1 row in set (0.00 sec)
mysql> SeLeCt vErSiOn();
+---------------------+
| vErSiOn()           |
+---------------------+
| 5.0.41-community-nt |
+---------------------+
1 row in set (0.00 sec)
mysql>

To test whether a connection can even be made, execute the command STATUS.

mysql>
mysql>
mysql> STATUS;
--------------
mysql  Ver 14.12 Distrib 5.0.41, for Win32 (ia32)
Connection id:          55
Current database:       test
Current user:           root@localhost
SSL:                    Not in use
Using delimiter:        ;
Server version:         5.0.41-community-nt MySQL Community Edition (GPL)
Protocol version:       10
Connection:             localhost via TCP/IP
Server characterset:    latin1
Db     characterset:    latin1
Client characterset:    latin1
Conn.  characterset:    latin1
TCP port:               3306
Uptime:                 10 days 23 hours 17 min 22 sec
Threads: 1  Questions: 34588  Slow queries: 0  Opens: 4294  Flush tables: 1  Open tables: 18  Queries per second avg: 0.036
--------------
mysql>

You can use mysql as a simple calculator:

mysql> SELECT SIN(PI()/4), (4+1)*5;
+------------------+---------+
| SIN(PI()/4)      | (4+1)*5 |
+------------------+---------+
| 0.70710678118655 |      25 |
+------------------+---------+
1 row in set (0.00 sec)
mysql>