Question

我正在尝试将事实表的ID设置为与我的维度表相同。

PRICE_TABLE             FACT_TABLE
P_ID                    P_ID
1                       0    
2                       0
3                       0
...                     ....

有没有人对此有好的方法？

UPDATE FACT_TABLE 
    SET FACT_TABLE.P_ID = PRICE_TABLE.P_ID 
    /* cannot seem to get a join here working */

我已尝试加入表格，但由于没有共同的价值观，我似乎无法让它发挥作用。

Answer 1

您可以使用select：

中的更新

UPDATE ft
SET ft.P_ID = pt.P_ID
FROM FACT_TABLE ft
LEFT JOIN PRICE_TABLE pt ON (pt.SomeField = ft.AnotherField) -- some join condition should be here

你也可以使用insert into select，如：

TRUNCATE TABLE FACT_TABLE; -- it will remove all data from your table
GO;
INSERT INTO FACT_TABLE (P_ID, other fields...) 
SELECT P_ID, other fields FROM PRICE_TABLE

Answer 2

您可以使用ROW_NUMBER来加入两个表中的记录，如下所示：

;WITH FACT_TABLE_RN AS (
   SELECT P_ID, 
          ROW_NUMBER() OVER (ORDER BY P_ID) AS rn
   FROM FACT_TABLE
), PRICE_TABLE_RN AS (
   SELECT P_ID, 
          ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS rn
   FROM PRICE_TABLE
)
UPDATE ft
SET P_ID = pt.P_ID
FROM FACT_TABLE_RN AS ft
JOIN PRICE_TABLE_RN AS pt ON pt.rn = ft.rn

Answer 3

目前，我可以向你求助。我想我们可以找到没有临时表的另一种方法。但它暂时应该做好工作。

with prices as
(
    select
        id = row_number() over(),
        P_ID
    from PRICE_TABLE
),
facts as
(
    select
        id = row_number() over()
        -- facts fieds you want
    from FACT_TABLE
)
select
    P_ID = prices.P_ID
    -- facts fieds you want
into #facts
from facts
    join prices on prices.id = facts.id

delete FACT_TABLE

insert FACT_TABLE
(
    P_ID
    -- facts fieds you want
)
select
    P_ID
    -- facts fieds you want
from #facts

drop table #facts

您可能必须取消选中FACT_TABLE.P_ID上的约束才能使用此脚本

如果我理解得很清楚，你的FACT_TABLE只包含你的P_ID，它来自PRICE_TABLE。为什么需要直接使用此FACT_TABLE而不是PRICE_TABLE？为什么不使用insert / select创建FACT_TABLE而不是尝试更新FACT_TABLE的P_ID字段？

填充事实表SQL Server

3 个答案: