write sql query in zend framework

To expand Bryan's answer :)

First, you have to create a "database adapter" what connects to your database. Each supported database engine has a specific adapter class. The database engine could be MySQL, PostgreSQL..etc you can find all here: http://framework.zend.com/manual/en/zend.db.adapter.html

For example you can create a MySQL specific adapter like this:

$dbAdapter = new Zend_Db_Adapter_Pdo_Mysql(array(
    'host'     => 'localhost',
    'username' => 'webuser',
    'password' => 'xxx',
    'dbname'   => 'test'
));

Then if you have a native SQL query, like:

$sql = "SELECT * FROM users WHERE id > 23";   

then you can use the above $dbAdapter object to run this native query, using its query() function:

$statement = $dbAdapter->query($sql);

Now the $statement variable will be a Zend_Db_Statement object. If you want to see the result of this query you can use the fetch() function, like:

while ($row = $statement->fetch()) {
    echo $row['username'];
}

While its easy to use, its not the best technique to use the above query() method because it not helps to promote database-independent queries. To write database independent queries you can use Zend_Db_Select. But of course, sometimes its not avoidable to use native queries. You can find here an example how can you write these queries for more db engines:
Zend_Db_Select order by random, compatible in mssql / mysql

Based on this example you can use different queries based on your adapter's type..