mysql让一个字段等于两个字段拼接

现有: 

         

目标: 

          

# 实现方法:
update purchase_goods set goods_name = concat(goods_id, ".  ", goods_name) 
# update 表名 set 字段1 = concat(字段a , "任意字符串", 字段b)


# 数据还原
update  purchase_goods set goods_name = substring_index(goods_name, ' ', -1)where goods_id =1
"""

"""