I am trying to figure out if and how I can create a select by attributes tool for a map service within ARCGIS Online, since the tool is not available on that program. I was wondering if there is a script I could run in the API that would do this, or if I could somehow incorporate python script into ARCGIS Online, since I know the python code to run a selection by attributes.
For the layer that you uploaded from ArcMap - when you view the Item Details for that layer from within AGOL, have you "Enabled" editing in the Properties at the bottom of the Details page then Saved?