PHP/MSSQL - Filtering from User Input (HTML)

Question

I have been given this assignment, to include some sort of filtering to my current SQL query via User Input. Basically, i am looking for a filtering option, whether its some kin

Answer 1

there should not be ANY data from user in sql query

that did not pass filter

sql-injection is not an empty word

so no $_GET['week'] in sql if you didn't clear it