How to subtract years from sysdate

Question

What would be the expression to check if someone\'s 20 years or over without hard-coding the date?

In the SQL

 SELECT student_fname 
 FROM students
 WHE         


        

Answer 1

WHERE dob < add_months( trunc(sysdate), -12*20 );

would work assuming that you want to ignore the time component of sysdate.