Process Query Language (PQL) is a special-purpose programming language for managing process models based on information about process instances that these models describe. PQL is based upon temporal logic and adopts the concrete syntax of SQL.
The PQL Tool is an open-source initiative that works on implementing an environment for executing PQL queries. The projected is hosted here.
The screencast below demonstrates the integration and usage of the PQL Tool in the open source process model repository Apromore.