/* How do I find a duplicate record? */
/* below will tell me if there are multiple students with same fname & sex */

SELECT fname, sex, COUNT(*)
FROM student
GROUP BY fname, sex
HAVING count(*) > 1;



/* From the above -   */
/* Now that I know, that there are multiple rows  */
/* I want the rest of the data from that table    */
/* inline views will be covered in the future     */

SELECT *  				/* or whatever columns you need */
FROM student  o, 
   ( SELECT fname, sex, COUNT(*)	/* inline view */
     FROM student 
     GROUP BY fname, sex
     HAVING count(fname) > 1  
   ) i
WHERE o.fname = i.fname			/* correlated subquery */
  AND o.sex   = i.sex;