Simpler method to apply filters

[ifokkema]

LOVD needs a simpler method to apply filters
LOVD allows for very complex filters, but users often don't know the syntax. New users won't know the values to search for. Many commercial websites have a filter menu, that allows selecting unique values for certain fields, or to apply ranges to certain values. Usually, these screens then indicate how many entries are available for those values. Implementing something like this would help LOVD users a lot.

• Decide on how to display this - a column left of the data table, a field-specific dropdown, or a field-specific dialog?
  • Considering the many different displays that LOVD has, it's going to be difficult to calculate a lot of values. Per field, calculating the unique values on request by storing the main query into a subquery and letting the database group per field, is probably the best solution.
  • Make sure numbers are shown, so users have an idea of statistics as well.
• Don't immediately apply the filter, only when the user is done selecting values and chooses the apply the filtering.
  • Selecting options applies filters to the data field.
• Disabling filters works the same way.
• Make this compatible with existing filters in the field.
• Also add a graph of the variant effect on the graphs page.