Your first step should be to review the tips and resources posted in the forum answers here and here. If your question is specific to use of tables in our system you should feel free to contact us at datalab@noao.edu or post a question to the forum itself. If you are asking for advice on a particularly complex query we may be able to help with suggested changes to the SQL or the workflow you are using, however we cannot promise to work out a solution in detail. When asking as question, please include as much information as you can about what you are trying to accomplish so we can more easily understand what your query is intended to do.