How to refresh the contents within the Python TKINTER Tab?

Try to fetch the values again and then insert the new values after deleting the existing values, like:

def refresh_clicked(self):    command = """SELECT et.`Equipment Type`, COUNT(i.`Equipment Type`) Total, SUM(IF(`Status`='Unavailable',1,0)) Unavailable, SUM(IF(`Status`='Available',1,0)) Available FROM `Equipment Types` et LEFT JOIN Inventory i ON et.`Equipment Type` = i.`Equipment Type` GROUP BY 1 ORDER BY 1"""    mycursor.execute(command)    display = mycursor.fetchall()        self.tree.delete(*self.tree.get_children()) # Delete all times inside the treeview        for row in display:        self.tree.insert('','end',value=row) # Insert newly fetched values  

Note that I used self.tree, so you need to declare the Treeview with self.tree and do all other methods with self.tree and so on.

I am not currently in front of a system, so I hope this code works and is not tested yet, let me know for any mistakes and changes.

you can use

for widgets in yourwidgetname.winfo_children():    widgets.destroy()

and reinitialize it by calling the function that initialize them

you can destroy all the widgets in a Frame by this way and it wont destroy completely your frame. it will destroy its child widgets.