[MySQL Tutorial 4] Selecting Database and Table

In the previous PHP tutorial on creating database, you learnt how to create and delete a database in MySQL. In this tutorial, you will learn how to select database and table.

Every database consists of tables that store data. To check the tables of a database, first select that database by the following command:

Use database_name;

Where database_name is the name of any database you want to select. For example;

Use mysql;

This can be done using PHP as follows:

<?php

$link=mysql_connect('localhost','root','your_password');

mysql_select_db('mysql');

echo "connected to mysql";

?>

 

This command selects “mysql” database. The output is shown as follows:

Now, to check which tables this database has, use the following:

Show tables;

This command will display a list of all the tables in “mysql” database. To see the contents of a particular table, you need to use select query which is as follows:

Select * from table_name;

For example,

Select * from user;

This command will display the contents of “user” table.

Suppose we have created a database named “new2” with a table “example2”. And the table contains salary and employee id as two columns.

As described above, we select the table “example2” from “new2” database as follows:

Use new2;

Select * from example2;

 

The output is as follows:

To do this using PHP program, put this command in mysql_query function as follows:

<?php

$link=mysql_connect('localhost','root','your_password');

mysql_select_db('new2');

echo "connected to new2";

$r=mysql_query("select * from example2");

$ro=mysql_fetch_array($r);

echo "<table border='1'>";

echo "<tr><th>sal</th><th>empid</th></tr>";

echo "<tr><td>";

echo $ro['sal'];

echo "</td><td>";

echo $ro['empid'];

echo "</td></tr>";

echo "</table>";

?>

The output will be shown as:

Mysql_fetch_array function is used to to fetch the data from select query, which is then displayed in a tabular format in the browser using html tags. Mysql_select_db function is used for select the particular database.

Now that you know how to select database and table, continue with the next tutorial on how to create a table within a database. Also, if you have any query, please leave a comment below.