摘要:
1.因式分解 例1:分解下列多项式 代码如下: from sympy import symbols, factor x, y = symbols('x y') f = 3 * x ** 4 - 2 * x ** 3 * y + 3 * x ** 3 - x ** 2 * y ** 2 - 2 * x 阅读全文
摘要:
1.获取2019-2020年每个月份的充值总额 USE xchat; SELECT month(update_time) as month,sum(amount) FROM charge_record WHERE buss_type=0 and charge_status=2 and charge_ 阅读全文