How to schedule an email using dates from an sql Table in python

I want to send a Reminder to the users email that has their inputted text as the contents using the dates from a sql database that the user enters. I am getting the inputs from a PYQT Page but i wont need any help with that as ive got the inputs into a table.

This is my database:My Database

And this is the code i am using to get the information and the way i am sending emails at the moment.

    connection = sqlite3.connect("CURRENTUSER.db")     crsr = connection.cursor()     crsr.execute('SELECT User FROM USER WHERE ID = 1 ')    CurrentUser = crsr.fetchall()    CurrentUser = str([CurrentUser])    CurrentUser = CurrentUser.replace('[', '')    CurrentUser = CurrentUser.replace(']', '')    CurrentUser = CurrentUser.replace('(', '')    CurrentUser = CurrentUser.replace(')', '')    CurrentUser = CurrentUser.replace(',', '')    CurrentUser = CurrentUser.replace("'" , '')    connection = sqlite3.connect("Emaildatabase.db")     crsr = connection.cursor()     crsr.execute('SELECT Email FROM Email WHERE Username = ? ', (CurrentUser,))    Mail = crsr.fetchall()    Mail = str(Mail)    Mail = Mail.replace('[', '')    Mail = Mail.replace(']', '')    Mail = Mail.replace('(', '')    Mail = Mail.replace(')', '')    Mail = Mail.replace(',', '')    Mail = Mail.replace("'" , '')        ReminderDate = self.Reminder_Date.date().toPyDate()    DueDate = self.Due_Date.date().toPyDate()    ReminderTime = self.Reminder_Time.time().toString()    DueTime = self.Due_Time.time().toString()    ReminderDate = str(ReminderDate)    ReminderDate = ReminderDate.replace("-","/")    DueDate = str(DueDate)    DueDate = DueDate.replace("-","/")    Input = self.Info_Input.toPlainText()    Connection = sqlite3.connect("Reminders.db")    crsr = Connection.cursor()    crsr.execute ("SELECT ID FROM Reminder")    ID = crsr.fetchall()    IDLen = len(ID)    CurrentID = (IDLen + 1)    CurrentID = str([CurrentID])    CurrentID = CurrentID.replace('[', '')    CurrentID = CurrentID.replace(']', '')    CurrentID = CurrentID.replace('(', '')    CurrentID = CurrentID.replace(')', '')    CurrentID = CurrentID.replace(',', '')    CurrentID = CurrentID.replace("'", '')    Update = ("INSERT INTO Reminder (DueDate, ReminderDate, ReminderTime, DueTime, Text, ID) VALUES (?, ?, ?, ?, ?, ? )")    Values = [(DueDate, ReminderDate, ReminderTime, DueTime, Input, CurrentID)]    crsr.executemany(Update, Values)    Connection.commit()    yag = yagmail.SMTP('pythontest22222@gmail.com', 'phAR7b1H2uqII5G8YR')    contents = [" HElllOOOO"        ]    yag.send(Mail, 'Your Set Reminder', contents)

I did find a way to schedule emails but they were set using the code not using variables or SQL Data.

    send_time = dt.datetime(2018,8,26,3,0,0) # set your sending time in UTC    time.sleep(send_time.timestamp() - time.time())

I still dont know how to get the dates from the table to be then used by the the program to schedule the email.