虽然FPDF中的循环只是第一次检索数据。它以pdf格式打印表格，但不输入第一次检索到的数据

I am printing a table filled with the data retrieved from database in PDF using FPDF library. I want this code to run until the end and print the data of students in groups in the table.It is retrieving and printing the data perfectly for the first group but for the other groups it prints only the table and doesn't populate it with the data. here is my code.I am printing a table filled with the data retr