SUM求和
课程：SQL · 编程练习
SQL编程练习 - SUM求和
练习内容
-- 计算订单总金额\nSELECT SUM(amount) AS total_amount FROM orders;\n\n-- 计算每个用户的订单总额\nSELECT user_id, SUM(amount) AS total\nFROM orders\nGROUP BY user_id;\n\n-- 计算已完成订单的总金额\nSELECT SUM(amount) AS completed_t
课程：SQL · 编程练习
SQL编程练习 - SUM求和
-- 计算订单总金额\nSELECT SUM(amount) AS total_amount FROM orders;\n\n-- 计算每个用户的订单总额\nSELECT user_id, SUM(amount) AS total\nFROM orders\nGROUP BY user_id;\n\n-- 计算已完成订单的总金额\nSELECT SUM(amount) AS completed_t