Question

how to execute SQL with if condition in c#?

This is my query and went i execute this query i get an error saying “Invalid SQL statement; expected ‘DELETE’, ‘INSERT’, ‘PROCEDURE’, ‘SELECT’, or ‘UPDATE’.”
I m using MS ACCESS as back end

     mycon.ConnectionString = ConnString;
            mycon.Open();

            string mySelectQuery = "IF (EXISTS (SELECT * FROM Employee AS t1 WHERE t1.ssn ='"+textBox4.Text+"' "+
                                    "))begin UPDATE Employee  SET "+
                                    "fname ='"+textBox1.Text+"' ,"+
                                    "minit ='"+textBox2.Text+"' ," +
                                    "lname ='" + textBox3.Text+"', " +
                                    "ssn ='" +textBox4.Text+"', " + 
                                    "bdate ='" +textBox5.Text+"', " +
                                    "address ='" +textBox6.Text+"', " +
                                    "sex ='" +textBox7.Text+ "', " +
                                    "salary ='" +textBox8.Text+"', " +
                                    "superssn ='" +textBox9.Text+"', " +
                                    "dno ='" +comboBox2.Text+"'" +
                                   " WHERE ssn = '"+textBox4.Text+"' "+
                                    "end "+
                                    "else "+
                                   " begin "+
                                   " INSERT INTO employee  values ('"+textBox1.Text+"','"+textBox2.Text+"','"+textBox3.Text+"','"+textBox4.Text+"','"+textBox5.Text+"','"+textBox6.Text+"','"+textBox7.Text+"','"+textBox8.Text+"','"+textBox9.Text+"','"+comboBox2.Text+"')"+
                                    " end";

            OleDbCommand myCommand = new OleDbCommand(mySelectQuery, mycon);

           int Success=  myCommand.ExecuteNonQuery();

Answer 1

MS Access doesn’t support the IF statement. Nor else or begin. You’ll have to do this in your C# code, such as performing your "SELECT * FROM Employee AS t1 WHERE t1.ssn ='"+textBox4.Text + "'"; query first and then performing the next one if there are results.

Also, you should either use a parameterized queries or escape the values of you text boxes.