Question

I am doing a college attendance project (Winforms, Mysql, C#)

I want to update 0 to P, 1 to Ab and 2 to OD in all period columns. For that I write a for loop and three update query.

Is it any possible idea for do this in one single query?

Please help me…

 for (int i = 1; i <= 8; i++)
            {
                string period = "Period" + i;
                string t1p = period1;

                command.CommandText = "update attendance_daily_rpt set " + t1p + " = 'P' where " + t1p + " = 0";
                connection.Open();
                command.ExecuteNonQuery();                
                connection.Close();

                command.CommandText = "update attendance_daily_rpt set " + t1p + " = 'Ab' where " + t1p + " = 1";
                connection.Open();
                command.ExecuteNonQuery();
                connection.Close();

                command.CommandText = "update attendance_daily_rpt set " + t1p + " = 'OD' where " + t1p + " = 2";
                connection.Open();
                command.ExecuteNonQuery();
                connection.Close();
            }

Thanks in advance…

Answer 1

SQL:

SET t1p = 
CASE t1p
 WHEN '1' THEN 'AB'
 WHEN '2' THEN 'OD' 
END

Make C# string yourself 😉