The SELECT statement includes a reserved word or an argument name that is misspelled or missing, or the punctuation is incorrect.

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C#3.5

private void button3_Click(object sender, EventArgs e)
{
DateTime vdateFrom = GC.getDueDateFrom();
DateTime vdateTo = GC.getDueDateTo();
string getAllData = "Select P_Id,P_Password,Format(Treat_Due_Date,\"dd/MM/yyyy\") As DueDate,P_Name,P_City,medicineTaker, from patient_Details,Treatment_Details Where patient_Details.P_ID = Treatment_Details.Treat_P_ID AND Treat_Due_Date > #" + vdateFrom.ToString("dd/MM/yyyy") + "# AND Treat_Due_Date < #" + vdateTo.ToString("dd/MM/yyyy") + "#";
bindGrid(getAllData);
}