There was no syntax error in the flow example you supplied in post 18, so that should have worked for you. You have to give the flow and inputs, you need help with, otherwise how can we see the issues causing you problems. Please in future respond to all questions and supply the flow and content with the issue in.
You can set the the date time format in the chart node in the x-axis label field. Select one of the options or use custom, you can the add you format using YYYY-MM-DD HH:mm:ss. or any combination of these plus Day, Month etc.
