MYSQL Insert...on duplicate value insert again with increment <p>I have 5 columns a, b, c, d and e. I want to insert values into first 4 columns and have kept default value as 1 in last column. I have kept the first 4 columns as primary keys. If duplicate values are inserted in the first 4 columns, then I want to insert the same values again but with increment in the 5th column. Eg: if 1,2,3,4 are values for the first 4 columns. then when 1,2,3,4 comes again they need to be inserted as 1,2,3,4 but with fifth column as 2.</p>