How to convert all tables from MyISAM into InnoDB?

<?php
    // connect your database here first 
    // 

    // Actual code starts here 

    $sql = "SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES
        WHERE TABLE_SCHEMA = 'your_database_name' 
        AND ENGINE = 'MyISAM'";

    $rs = mysql_query($sql);

    while($row = mysql_fetch_array($rs))
    {
        $tbl = $row[0];
        $sql = "ALTER TABLE `$tbl` ENGINE=INNODB";
        mysql_query($sql);
    }
?>

Run this SQL statement (in the MySQL client, phpMyAdmin, or wherever) to retrieve all the MyISAM tables in your database.

Replace value of the name_of_your_db variable with your database name.

SET @DATABASE_NAME = 'name_of_your_db';

SELECT  CONCAT('ALTER TABLE `', table_name, '` ENGINE=InnoDB;') AS sql_statements
FROM    information_schema.tables AS tb
WHERE   table_schema = @DATABASE_NAME
AND     `ENGINE` = 'MyISAM'
AND     `TABLE_TYPE` = 'BASE TABLE'
ORDER BY table_name DESC;

Then, copy the output and run as a new SQL query.