Query Language Restrictions and Unsupported Features

At a high level, GemFire does not support the following querying features:

GROUPBY is not supported.
Indexes targeted for joins across more than one region are not supported
Static method invocations. For example, the following query is invalid:
```
SELECT DISTINCT * FROM /QueryRegion0 WHERE aDay = Day.Wednesday
```
Aggregate functions are not supported.
You cannot create an index on fields using Set/List types (Collection types) that are not comparable. The OQL index implementation expects fields to be Comparable. To workaround this, you can create a custom Collection type that implements Comparable.
ORDER BY is only supported with DISTINCT queries.

In addition, there are some specific limitations on partitioned region querying. See Partitioned Region Query Restrictions.