Question

Suppose I have a SQL table “Celebrities” with two columns: “fname” and “lname”:

fname    | lname    
---------+-------  
Bill     | Clinton
Bill     | Gates
George   | Bush
George   | Clinton
Barack   | Obama

I would like to write a query that returns the first and last name of each person in the table whose last name appears at least twice in the column “lname”. How do I write this SQL query?

Answer 1

SELECT fname, lname FROM Celebrities 
WHERE lname IN 
 (SELECT lname FROM Celebrities 
  GROUP BY lname HAVING COUNT (lname) >1)