On 12 Dec 2015, at 7:52pm, Cecil Westerhof <cldwesterhof at gmail.com> wrote:
> ?Here http://www.tutorialspoint.com/sqlite/sqlite_indexes.htm it is said > that you should not use an index on columns that use a high number of NULL > values. At the moment that is true. So I should not use an Index?? The tutorial thinks that you would use the index to pick out specific values in the column. Your own use is to differentiate between columns which have values and those which don't. Try it. Create the index. I promise it won't corrupt your database. Check to see whether it improves your times for the SELECT I quoted. If it turns out not to improve things then you can delete the index with no harm done. Simon.
