Question

我有桌子：

带有值的

价格（sellerId，usdBidPrice，usdAskPrice，eurBidPrice，eurAskPrice，gbpBidPrice，gbpAskPrice）

(1, 1, 1.1, 1.14, 1.16, 0.8, 0.9)

带有值的

货币（ccyId，ccyDescription）

(1, 'USD'),
(2, 'EUR'),
(3, 'GBP')

期望的输出：

sellerId    AvgPrice    Ccy
1           1.05        1
1           1.15        2
1           0.85        3

我有这个工作样本，但不喜欢硬编码的值，没有它有什么选择吗？

DECLARE @usdId INT;
DECLARE @eurId INT;
DECLARE @gbpId INT;

SELECT @usdId = ccyId 
FROM Currency (NOLOCK)
WHERE [description] = 'USD'

SELECT @eurId = ccyId 
FROM Currency (NOLOCK)
WHERE [description] = 'EUR'

SELECT @gbpId = ccyId 
FROM Currency (NOLOCK)
WHERE [description] = 'GBP'

SELECT
      sellerId,
      avgPrice,
      CASE currencyType 
        WHEN 'USD' THEN @usdId
        WHEN 'EUR' THEN @eurId
        WHEN 'GBP' THEN @gbpId
        ELSE NULL
    END AS Ccy
FROM
( 
      SELECT
            sellerId,
            (usdBidPrice + usdAskPrice) / 2 AS USD,
            (eurBidPrice + eurAskPrice) / 2 AS EUR,
            (gbpBidPrice + gbpAskPrice) / 2 AS GBP
      FROM Prices (NOLOCK)
) pricesRawData
unpivot
(
    avgPrice for currencyType in (USD, EUR, GBP)
)marks

Answer 1

您需要动态SQL和UNPIVOT：

SELECT  sellerId,
        AVG([Values]) as AvgPrice,
        ccyId
FROM (
    SELECT *
    FROM #Prices) p
UNPIVOT (
    [Values] FOR Price in ([USDBidPrice],[USDAskPrice],[EURBidPrice],[EURAskPrice],[GBPBidPrice],[GBPAskPrice])
) unpvt
INNER JOIN #Currency c
    ON c.ccyDescription = LEFT(Price,3)
GROUP BY sellerId, ccyId

打印结果：

sellerId    AvgPrice    ccyId
1           1,05        1
1           1,15        2
1           0,85        3

执行后，您将获得此输出：

Render

不同列的不透明

1 个答案: