LeetCode:Database 113.银行账户概要
Posted Xiao Miao
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要求:写一条 SQL 语句,查询:user_id 用户 ID,user_name 用户名,credit 完成交易后的余额,
credit_limit_breached 检查是否透支 (“Yes” 或 “No”),以任意顺序返回结果表。
力扣银行 (LCB) 帮助程序员们完成虚拟支付。我们的银行在表 Transaction 中记录每条交易信息,我们要查询每个用户的当前余额,并检查他们是否已透支(当前额度小于 0)。
用户表: Users的结构
+--------------+---------+
| Column Name | Type |
+--------------+---------+
| user_id | int |
| user_name | varchar |
| credit | int |
+--------------+---------+
user_id 是这个表的主键。
表中的每一列包含每一个用户当前的额度信息。
交易表:Transactions的结构
+---------------+---------+
| Column Name | Type |
+---------------+---------+
| trans_id | int |
| paid_by | int |
| paid_to | int |
| amount | int |
| transacted_on | date |
+---------------+---------+
trans_id 是这个表的主键。
表中的每一列包含银行的交易信息。
ID 为 paid_by 的用户给 ID 为 paid_to 的用户转账。
Users 表:
+------------+--------------+-------------+
| user_id | user_name | credit |
+------------+--------------+-------------+
| 1 | Moustafa | 100 |
| 2 | Jonathan | 200 |
| 3 | Winston | 10000 |
| 4 | Luis | 800 |
+------------+--------------+-------------+
Transactions 表:
+------------+------------+------------+----------+---------------+
| trans_id | paid_by | paid_to | amount | transacted_on |
+------------+------------+------------+----------+---------------+
| 1 | 1 | 3 | 400 | 2020-08-01 |
| 2 | 3 | 2 | 500 | 2020-08-02 |
| 3 | 2 | 1 | 200 | 2020-08-03 |
+------------+------------+------------+----------+---------------+
Result Table:
+------------+------------+------------+-----------------------+
| user_id | user_name | credit | credit_limit_breached |
+------------+------------+------------+-----------------------+
| 1 | Moustafa | -100 | Yes |
| 2 | Jonathan | 500 | No |
| 3 | Winston | 9900 | No |
| 4 | Luis | 800 | No |
+------------+------------+------------+-----------------------+
Moustafa 在 "2020-08-01" 支付了 $400 并在 "2020-08-03" 收到了 $200 ,当前额度 (100 -400 +200) = -$100
Jonathan 在 "2020-08-02" 收到了 $500 并在 "2020-08-08" 支付了 $200 ,当前额度 (200 +500 -200) = $500
Winston 在 "2020-08-01" 收到了 $400 并在 "2020-08-03" 支付了 $500 ,当前额度 (10000 +400 -500) = $9900
Luis 未收到任何转账信息,额度 = $800
SQL语句:
with a as(
select user_id as id,credit as credit from users
union all
select paid_by as id,-amount as credit from transactions
union all
select paid_to as id,amount as credit from transactions),
b as
(select id,sum(credit) as credit
from a
group by id)
select b.id as user_id,c.user_name as user_name,b.credit as credit,if(b.credit<0,'Yes','No') as credit_limit_breached
from b
join users c
on b.id=c.user_id;
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