Error Messages (U) A B C D E F G H I J K L M N O P Q R S T U V W X Y Z #Unable to understand SQL Request. (1691) "Unable to understand SQL Request. (1691)" is a Progress specific error message. This message implies that the Progress database could not understand the SQL statement, which is passed by the client application. If you experience "SQL Request" errors, take the following action:1. Identify the SQL statement that is passed to the database. You may need to generate a clientside ODBC trace, if you use an application that autogenerates SQL.2. Look at the statement for obvious flaws or elements that may inhibit Progress's ability to process it. For example, Progress SQL89 databases prohibit the use of the keyword AS for column aliasing.3. Pass the problem statement to Progress using a simple program such as OpenLink's odbctest (Unix) or C++ Demo (Windows). See if the error reoccurs.4. Pass the problem statement to Progress using a Progress native interface such as clidemo. See if the error reoccurs.Finally, if you are unable to determine the source of the problem, submit a trace and the outcomes of the tests described in steps #3 and #4. Additionally, state whether or not your Progress runs in SQL89, SQL92, or mixed mode.