I've no idea, you need to provide the query. Also be sure to test with debug mode and maximum error reporting enabled in Joomla global configuration to ensure errors are completely output. The query select fields need additional configuration beyond just adding a query. You need to specify what columns that are being output should be used for the options value and label. See the below videos for query field usage.
www.youtube.com/playlist?list=PLp0puRITgC7MM9iP9FooKB1qk8f5MLWVp