SQL-Deleting Duplicate Records from a Table

Q How to delete duplicate records from a table ?
      This is one of the famous question asked by  an interviewer. Lets us see how to to delete duplicate records from a table. Table StudentInfo has duplicate records as shown below.

SudentInfo Table

Step 1: First we will create a temporary table say temp and copy all original table (StudentInfo Table) data into this very temporary table.