pymysql原生语句案例

 # 1. 查询所有商品信息
 def __fetch_all_info(self):
     cur = self.db_connect.cursor()
     sql_str = '''select * from goods'''
     cur.execute(sql_str)
     result = cur.fetchall()
     self.__show_query_result(result)
     cur.close()

# 2. 查询所有包含商品的分类
 def __fetch_cate_of_goods(self):
     cur = self.db_connect.cursor()
     sql_str = '''select distinct good_cates.name from goods inner join good_cates on goods.cate_id = good_cates.id;'''
     # sql_str = ''' select name from good_cates where id in (select distinct cate_id from goods); '''
     cur.execute(sql_str)
     result = cur.fetchall()
     self.__show_query_result(result)
     cur.close()

 # 3. 添加商品分类
 def __add_new_cate(self):
     new_cate = input('请输入一个新商品分类:')
     sql_str = ''' insert into good_cates(name) values("%s") ''' % new_cate
     cur = self.db_connect.cursor()
     cur.execute(sql_str)
     self.db_connect.commit()
     cur.close()

 # 4. 将所有商品价格加1000
 def __update_price(self):
     cur = self.db_connect.cursor()
     sql_str = ''' update goods set price = price + 1000'''
     cur.execute(sql_str)
     self.db_connect.commit()
     cur.close()

# 5. 将所有笔记本的分类改为超级本
def __update_cate(self):
    cur = self.db_connect.cursor()
    sql_str = '''update goods set cate_id = (select id from good_cates where name = '超级本') where name like '%笔记本%';'''
    cur.execute(sql_str)
    self.db_connect.commit()
    cur.close()

# 6. 根据id查询商品信息
def __fetch_info_with_id(self):
    s_id = input('请输入一个商品ID:')
    sql_str = ''' select * from goods where id = %s ''' % s_id
    print(sql_str)
    cur = self.db_connect.cursor()
    cur.execute(sql_str)
    result = cur.fetchall()
    self.__show_query_result(result)
    cur.close()

# 7. 根据id查询商品信息安全方式
def __fetch_info_with_id_safe(self):
    s_id = input('请输入一个商品ID:')
    sql_str = ''' select * from goods where id = %s '''
    print(sql_str)
    cur = self.db_connect.cursor()
    cur.execute(sql_str, (s_id,))
    result = cur.fetchall()
    self.__show_query_result(result)
    cur.close()