IIF 或 CASE 子句中的 MONEY 数据类型 CAST 问题

Question

这是一个生成正确输出的示例查询示例：

DECLARE @T TABLE (
    keydate DATE,
    price   MONEY
);

INSERT INTO @T(keydate, price) VALUES
('2014-07-23', 32464),
('2014-07-26', 32478),
('2014-07-27', 32473)


;WITH
cte_tbl (keydate, price, prev_price1)
AS (
SELECT TOP(1) 
    T.keydate,
    T.price,
    T.price AS prev_price
    FROM @T AS T
    ORDER BY T.keydate
UNION ALL
SELECT
    T.keydate,
    T.price,
    T.prev_price
    FROM (
    SELECT
        TT.keydate,
        TT.price,
        IIF(ABS(TT.price - cte_tbl.prev_price1) < 10, cte_tbl.prev_price1, TT.price) AS prev_price,
        ROW_NUMBER() OVER(ORDER BY TT.keydate) AS ROWNUM
        FROM @T AS TT
        INNER JOIN cte_tbl ON cte_tbl.keydate < TT.keydate
    ) AS T
    WHERE T.ROWNUM = 1
)

SELECT *
FROM cte_tbl 
ORDER BY keydate

正确的输出是：

keydate price       prev_price1
2014-07-23  32464.00    32464.00
2014-07-26  32478.00    32478.00
2014-07-27  32473.00    32478.00

如果我更改为带点的 MONEY 的十进制价格：

INSERT INTO @T(keydate, price) VALUES
('2014-07-23', 324.64),
('2014-07-26', 324.78),
('2014-07-27', 324.73)

输出将是错误的:

keydate price   prev_price1
2014-07-23  324.64  324.64
2014-07-26  324.78  324.64
2014-07-27  324.73  324.64

价格实际上在CTE声明中，但它不拒绝乱七八糟的。

我需要将它们存储为正常价格并具有如上所述的正确输出行为：

('2014-07-23', 324.64),
('2014-07-26', 324.78),
('2014-07-27', 324.73)

输出应该是：

keydate price       prev_price1
2014-07-23  32464.00    324.64
2014-07-26  32478.00    324.78
2014-07-27  32473.00    324.78

感谢您的帮助！

Answer 1

因为32464和32478' is more than 10, but the difference between324.64and324.78`没有区别。更改此行：

IIF(ABS(TT.price - cte_tbl.prev_price1) < 10, cte_tbl.prev_price1, TT.price)

至：

IIF(ABS(TT.price - cte_tbl.prev_price1) < 0.10, cte_tbl.prev_price1, TT.price)

如果要将价格降低 10 倍，则需要将比较值降低 10 倍。

IIF 或 CASE 子句中的 MONEY 数据类型 CAST 问题

MONEY Datatype CAST issue in IIF or CASE clause

sql-server

tsql

case

sqldatatypes