In Magento we can use addAttributeToFilter Conditions same as where in SQL.

Below are the all condtions:

Equals: eq

$_products->addAttributeToFilter('status', array('eq' => 1));

Not Equals - neq

$_products->addAttributeToFilter('sku', array('neq' => 'test-product'));

Like - like

$_products->addAttributeToFilter('sku', array('like' => 'UX%'));

One thing to note about like is that you can include SQL wildcard characters such as the percent sign.

Not Like - nlike

$_products->addAttributeToFilter('sku', array('nlike' => 'err-prod%'));

In - in

$_products->addAttributeToFilter('id', array('in' => array(1,4,98)));

When using in, the value parameter accepts an array of values.

Not In - nin

$_products->addAttributeToFilter('id', array('nin' => array(1,4,98)));

NULL - null

$_products->addAttributeToFilter('description', 'null');

Not NULL - notnull

$_products->addAttributeToFilter('description', 'notnull');

Greater Than - gt

$_products->addAttributeToFilter('id', array('gt' => 5));

Less Than - lt

$_products->addAttributeToFilter('id', array('lt' => 5));

Greater Than or Equals To- gteq

$_products->addAttributeToFilter('id', array('gteq' => 5));

Less Than or Equals To - lteq

$_products->addAttributeToFilter('id', array('lteq' => 5));