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.

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

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:

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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></source>

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

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mysql> mysql> mysql> STATUS;

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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

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mysql></source>

You can use mysql as a simple calculator:

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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></source>