How to query GQL for boolean value?

Question

There doesn't seem to be any documentation on how to query the datastore using boolean parameters in the where statement of a GQL query.

I have been trying to query an AppEngine datastore based on a boolean column, but it's not returning any results in the data viewer of the AppEngine dashboard.

I've tried the following:

SELECT * FROM users WHERE active=TRUE
SELECT * FROM users WHERE active=True

Any help would be greatly appreciated.

Answer 1

As per the documentation the correct syntax for GQL boolean comparisons is

SELECT * FROM users WHERE active = TRUE

See https://developers.google.com/appengine/docs/python/datastore/gqlreference

Now if you are not getting results then either the active attribute is not True for all entities or the attribute active is not in fact a bool type.

Just for completeness I performed the following query with expected results.

SELECT * FROM Plant where flowering = TRUE

Answer 2

I had to specify True / False (starting with uppercase T / F) for it to work in the query. However, it shows the boolean values in all lowercase in the datastore viewer.

Answer 3

you can use

    SELECT * FROM users WHERE active = true

make sure that true/false are in small case

this will definately work.

Answer 4

Please check whether you have an index on the filed you are filtering (in your case make sure that you have indexed "active" property in "users" entity)

I tried this experiment at my end and have seen that if there is no index, datastore doesn't return any results. This is explained in the documentation by Google: Datastore Indexes and the relevant paragraph is:

Every Datastore query computes its results using one or more indexes, tables containing entities in a sequence specified by the index's properties and, optionally, the entity's ancestors...