I regularly write SQL queries to check for certain conditions in my data. We've developed a system used to automate the calculation of Teacher Bonuses that are based on Student Assessment Scores. The system basically is dependent on the right data being in the right place at the right time, which doesn't always happen. Therefore, we use a number of SQL queries to identify conditions such as mismatched data or missing critical data. Although the development of the queries consumed a lot of time, the queries continue to pay great dividends when used in a proactive manner.