Php / mysql：在php数组中处理空sql结果

I've got, in this case, 4 radio buttons in a form. In a previous step a user gets to choose between options (like A, B, C, D) that include different radios being selected. Eg: Choose A and radio 1 is selected, and so on. This choice is saved in mysql asI've got, in this case, 4 radio buttons in a fo