This is my table
Sample(tablename) -Day_start(column1) -Day_end(column2) -Total_days(column3) -Days_left(column4)
Day_start(column1) -March 1 2017(data)
Day_end(column2) -April 5 2017(data)
Total_days(column3) -36 (data)
days_left(column4) -36(data)
Sorry for my last question, im not good in English!.. So this is my question In the day of March 2 2017 the days left must be 35. so everyday the days_left will decrease automatically I only know the code of between two dates whichis my total_days. But I dont know how to decrease it by 1 automatically per day . Then it will diplay in the table of netbeans