在以日期为键的 CTE 中插入 "missing records"

Question

我有一个具有以下结构的 CTE

ITEM,   DATE,       QUANTITY,   EXTRA
AAAA    01-07-2015  100         20
AAAA    04-07-2015  100         13
AAAA    07-07-2015  100         16
AAAA    09-07-2015  100         23
.
.
.
AAAA    31-07-2015  100         30

基本上，我想要做的是取出带有 'missing dates' 的记录，以及包含前一条记录中的 EXTRA 的 EXTRA 字段（如下所示）

ITEM,   DATE,       QUANTITY,   EXTRA
AAAA    01-07-2015  100         20
AAAA    02-07-2015  0           20
AAAA    03-07-2015  0           20
AAAA    04-07-2015  100         13
AAAA    05-07-2015  0           13
AAAA    06-07-2015  0           13
AAAA    07-07-2015  100         16
AAAA    08-07-2015  0           16
AAAA    09-07-2015  100         23
.
.
.
AAAA    31-07-2015  100         30

我可以使用 LAG 和包含完整有效日期列表 + MERGE 的临时文件 table 手动插入记录。然而，该CTE仅用于一次性检查然后被处置。有没有更好的方法？

Answer 1

考虑以下因素：

我制作了一个 CTE 代表您的数据（不考虑 ITEM 因为它与示例无关）。

对于以下两个 CTE，我正在使用 recursive query.

搜索可用 data 的最小值和最大值之间的缺失日期

接下来，您需要将右边的data加入可用的dates。关键是从 data 中获取最大 date 的行，只要 data.date 小于 dates.date.

最后，我根据例子的解释是你想继承extra，而不是quantity。因此 case-语句在 select.

with data as (
    select cast('2015-07-01' as date) date, 100 quantity, 20 extra union all
    select cast('2015-07-04' as date) date, 100 quantity, 13 extra union all
    select cast('2015-07-07' as date) date, 100 quantity, 16 extra union all
    select cast('2015-07-09' as date) date, 100 quantity, 23 extra
)

, maxDate as (
    select MAX(date) date
    from data
)

, dates as (
    select date
    from data

    union all

    select DATEADD(day,1,date) date
    from dates
    where DATEADD(day,1,date) not in (select date from data)
        and DATEADD(day,1,date) < (select date from maxDate)
)

select dates.date
, case dates.date when data.date then data.quantity else 0 end quantity
, data.extra
from dates
join data on data.date = (select max(date) from data where data.date <= dates.date)
order by 1

Answer 2

试试这个；

;with tbl as (
    --your data....
),
max_min_val as (
  select max(date) as max_date, min(date) as min_date from tbl
),
all_date AS (
    SELECT min_date as DateColumn 
    from max_min_val
    UNION ALL
    SELECT DATEADD(day,1,DateColumn)
    FROM all_date, max_min_val
    WHERE DATEADD(day,1,DateColumn) <= max_date
)
select 
    coalesce(t.item, (select top 1 tt.item from tbl tt where tt.date < x.DateColumn order by tt.date desc)) as item,
    x.DateColumn as date, 
    coalesce(t.QUANTITY, 0) as QUANTITY,
    coalesce(t.EXTRA, (select top 1 tt.EXTRA from tbl tt where tt.date < x.DateColumn order by tt.date desc)) as EXTRA
from all_date x
left join
tbl t on t.date = x.DateColumn

此处 all_date 将包含 min and max date in tbl 之间的所有 date。
左连接all_date 将给出所有日期
coalesce(t.QUANTITY, 0) as QUANTITY 将给出 t.QUANTITY if not null else 0
EXTRA 和 item 将根据 date.

CTE tbl

在以日期为键的 CTE 中插入 "missing records"

Inserting "missing records" in a CTE with dates as a key

tsql

sql-server

common-table-expression