如何計算CDS view裏兩個時間戳之間的天數間隔

ABAP透明表裏的時間戳，數據類型爲dec：

有個需求：計算這兩個時間戳之間的天數間隔，丟棄時間戳年-月-日8位後面的小時：分鐘：秒。

舉個例子：若是時間戳是20180918173132，丟棄173132，只保留20180918, 而後再計算天數間隔。

直接用CDS view的字符串操做函數substring是不行的，由於時間戳類型dec和substring期待的字符串類型不匹配。

解決方案：

先將時間戳字段類型從dec強制轉換成abap.dats：

@AbapCatalog.sqlViewName: 'zproday'

@AbapCatalog.compiler.compareFilter: true

@AccessControl.authorizationCheck: #CHECK

@EndUserText.label: 'Day between'

define view zdate_day_between as select from comm_product {

key comm_product.product_id as prod_id,

comm_product.product_guid as prod_guid,

comm_product.valid_from as valid_from,

comm_product.valid_to as valid_to,

cast(substring(cast(valid_from as abap.char(32)),1,8) as abap.dats) as from_date,

cast(substring(cast(valid_to as abap.char(32)),1,8) as abap.dats) as to_date

}

而後再用CDS view標準的時間處理函數DATS_DAYS_BETWEEN:

@AbapCatalog.sqlViewName: 'zdbetw'

@AbapCatalog.compiler.compareFilter: true

@AccessControl.authorizationCheck: #CHECK

@EndUserText.label: 'Day between'

define view zc_date_day_between as select from zdate_day_between as host{

key host.prod_guid,

host.prod_id,

host.from_date,

host.to_date,

DATS_DAYS_BETWEEN(host.from_date, host.to_date) as no_of_days

}

測試結果：

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