CelesteCS JQL Extensions plugin extends the standard Atlassian JIRA JQL functionality with a set of functions, which lets one to get sophisticated results with simple jcex.* function calls. The functions are available to be added to JQL queries as soon as the plugin is installed, no additional configuration is needed.
The power of CelesteCS JQL Extensions plugin is in the ability to effectively use internal JIRA APIs to get exactly what is needed without building huge JQL requests. Plus, the results are retrieved as standard JIRA objects, like Issues and DateTime, so no special filters or reports is needed to process these results.