Combine rows with logic from MySQL table and output to JSON

I have a MySQL table with multiple rows and on the JSON output I want to create a column tolerance and if the rows fit within that tolerance, combine the values and and average the tolerance column. See excel file for example of what I am trying to do. If the data on the left has a tolerance of 0.03 for the price column then the row is combined with the like rows. So the quantity is then added together and the price is then averaged. The rows that are body_row = 0 is a built in sum row for the symbol so that row is just ignored. My goal is that I can have a PHP file that does this on the fly and then uses json_encode to output the modified table data. Attached is the MySQL export of the data that I would like to use. In your proposal please tell me what color the highlighted rows are in the Excel spreadsheet so that I know that you opened the file. Thanks