I am trying to make a shiny app. I want to have an interactive menu such that by selecting an input "A" in the first SelectInput, R will look at the database and find a list of values that correspond to A, to come up as an option in second SelectInput.
The third selectInput to filter through columns based on the first two SelectInput.
What would the corresponding server code would be if I wanted to do a histogram or table with the result?
Thank you so much for your help