The Craft site shows an example using a single comparison
Building upon this example from that page:
craft.entries.width('>= 100')
Can I do something similar but where 'width' is ALSO less than or equal to 200?
Conceptually:
craft.entries.width('>= 100 && <= 200')
You can combine multiple criteria like so:
{% set entries = craft.entries.width('and, >= 100, <= 200') %}
but what you can't do is to combine multiple statements to build more complex criteria:
{% set entries = craft.entries.width('and, >= 100, <= 200' or '>= 500') %}
in your case this wouldn't make much sense. But see my still unanswered question on this topic for another example: "Complex logic on a ElementCriteriaModel parameter?"
You can use some basic logic with and or or like this:
craft.entries.width('and, >= 100, <= 200')
