Update questions.sql

Author: UzMatic

SQL Deep Dive/Null Values/questions.sql

@@ -3,10 +3,10 @@
 * DB: https://www.db-fiddle.com/f/PnGNcaPYfGoEDvfexzEUA/0
 * Question: 
 * Assuming a students minimum age for the class is 15, what is the average age of a student?
-*/
+*/SELECT avg(coalesce(age, 15)) FROM "Student";
 
 /*
 * DB: https://www.db-fiddle.com/f/PnGNcaPYfGoEDvfexzEUA/0
 * Question: 
 * Replace all empty first or last names with a default?
-*/
+*/SELECT id, coalesce(name,'firstname'),coalesce(lastName,'LastName'), age FROM "Student";