GQL: Find all entities that contain a substring

I have some entities that have a StringProperty and I would like to query for all the entities that match a substring. Is there a way to do that using just GQL?

For example, if my datastore looks like this开发者_如何学Go:

ID/Name     question_text
--------------------------------------------------------------
3001        I like to eat chicken.
3020        I only like to eat chicken that is deep fried.
3045        I like filet mignon.
3052        I like cheese.

What would the GQL query be to find all the entities that contain 'chicken' in question_text?

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What you're looking for is full-text search over a StringProperty. This is what SearchableModel was created for.

Basically, it creates a new property on your entity that is a list of all the strings (and I believe bi- and tri-grams) in the text field, using the task queue. Then searching for "chicken" is done by a GQL query like SELECT * FROM whatever WHERE 'chicken' IN strings_list