I have made a query showing the time a particular event happens each day. I would like to make a line chart so my team can easily see how the time of this event changes over the course of the week. However, when I go to the visualization tab, everything is grayed out except 'Table.' I can still select the 'Line' option, but on the 'Data' tab, it says 'No valid fields' under the Y axis selector, where I would normally choose the data to be displayed on the y axis (in this case, the time). Is there any way to display the data I am interested in? I am using MySQL and explicitly casting the columns to date and time, so I am confident there are no data type issues (like with a varchar).