更新sql

#将xv_bjdm班级给st_student

UPDATE st_student,
 xs_student
SET st_class = bjmc
WHERE
	st_student.student_id = xs_student.xh 

 # 将st_class转换成班级编码

UPDATE st_student,
 xv_bjdm
SET st_class = bjdm
WHERE
	st_student.st_class = xv_bjdm.bjmc