Question

我随时间收集了一些帐户余额：

/**
 * Reduces drag sensitivity of [ViewPager2] widget
 */
fun ViewPager2.reduceDragSensitivity() {
    val recyclerViewField = ViewPager2::class.java.getDeclaredField("mRecyclerView")
    recyclerViewField.isAccessible = true
    val recyclerView = recyclerViewField.get(this) as RecyclerView

    val touchSlopField = RecyclerView::class.java.getDeclaredField("mTouchSlop")
    touchSlopField.isAccessible = true
    val touchSlop = touchSlopField.get(recyclerView) as Int
    touchSlopField.set(recyclerView, touchSlop*8)       // "8" was obtained experimentally
}

每条记录均显示在指定时间戳记下客户的帐户总余额。帐户余额增加，例如当客户使用55充值时，从-35增至20。客户使用服务时，其帐户余额会减少，例如从5到-10。

我想用两种方式汇总这些数据：

1）获取每月和每年部门的借方，贷方和余额（贷方借方）。 4月的结果应该是以前所有月份的摘要：

+-----------------+------------+-------------+-----------------------+
| account_balance | department | customer_id |  timestamp            |
+-----------------+------------+-------------+-----------------------+
| 5               | A          | 1           |  2019-02-12T00:00:00  |
| -10             | A          | 1           |  2019-02-13T00:00:00  |
| -35             | A          | 1           |  2019-02-14T00:00:00  |
| 20              | A          | 1           |  2019-02-15T00:00:00  |
+-----------------+------------+-------------+-----------------------+

客户的帐户余额可能不会每月更改。 2月可能有客户1的帐户余额记录，但3月可能没有。

解决方案说明：

使用+---------+--------+-------+------------+-------+--------+ | balance | credit | debit | department | month | year | +---------+--------+-------+------------+-------+--------+ | 5 | 10 | -5 | A | 1 | 2019 | | 20 | 32 | -12 | A | 2 | 2019 | | 35 | 52 | -17 | A | 3 | 2019 | | 51 | 70 | -19 | A | 4 | 2019 | +---------+--------+-------+------------+-------+--------+
使用EXTRACT(MONTH from timestamp) month
EXTRACT(YEAR from timestamp) year

2）按日期获取部门借方，贷方和余额的变化。

GROUP BY month, year, department

当我创建增量的总和时，我应该从1）中的结果中获取与最后一行相同的值。

解决方案说明：

使用+---------+--------+-------+------------+-------------+ | balance | credit | debit | department | date | +---------+--------+-------+------------+-------------+ | 5 | 10 | -5 | A | 2019-01-15 | | 15 | 22 | -7 | A | 2019-02-15 | | 15 | 20 | -5 | A | 2019-03-15 | | 16 | 18 | -2 | A | 2019-04-15 | +---------+--------+-------+------------+-------------+ 51 70 -19计算增量

Answer 1

您的问题尚不清楚，但是听起来您想在任何给定的时间点获得未偿还的余额。

以下查询在1个时间点执行此操作。

with calendar as (
  select cast('2019-06-01' as timestamp) as balance_calc_ts
),
most_recent_balance as (
  select customer_id, balance_calc_ts,max(timestamp) as most_recent_balance_ts
  from <table>
  cross join calendar
  where timestamp < balance_calc_ts -- or <=
  group by 1,2
)
select t.customer_id, t.account_balance, mrb.balance_calc_ts
from <table> t
inner join most_recent_balance mrb on t.customer_id = mrb.customer_id and t.timestamp = mrb.balance_calc_ts

如果需要在一系列时间点进行计算，则需要修改日历CTE以返回更多日期。这就是BQ中CROSS JOINS的美丽！

在BigQuery中切片帐户余额数据以生成借方报告

1 个答案: