SQL Server Management Studio
As part of the Microsoft SQL Server Client Tools package, SQL Server Management Studio (Query Analyzer) is a handy tool that allows you to query the database directly using Transact SQL. It is essentially a window in SQL Server through which you can execute custom SQL queries. Many of the stored procedures executed by the Plant Applications Administrator Troubleshooting tools (i.e. spSupport_ShowRunning and spSupport_ShowBlocking) can be executed directly from Management Studio.
Management Studio is also your main development arena for custom calculations, reporting and event stored procedures. It provides a number of handy features that allow evaluation of the performance of custom Transact SQL code.
For more information, please see your SQL Server Books Online.