Sql 如果列值为X，则计算百分比

我有一个表，下面有列：

• 成本
• 销售渠道
• 产品销售商

如果满足某些值，我想对成本进行不同的计算

i、 e

if Sales Channel = Mobile, and Product Seller = Mark, then take 8% off cost

if sales channel = desktop, and product seller = James, then take 5% off cost

我试过：

select
channel,
acct_mgmr,
cost
(cost*0.05) as A
(cost*0.08) as B

from db.table

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理想情况下，能够根据渠道和销售经理查看最终销售价格…值根据列的组合而变化

您可以使用

案例

调整每个用例的计算：

SELECT
    channel,
    acct_mgmr,
    CASE
        WHEN ( Sales_Channel = 'Mobile' AND Product_Seller = 'Mark' )   THEN cost * 0.92
        WHEN ( Sales_Channel = 'desktop' AND Product_Seller = 'James')  THEN cost * 0.95
        ELSE cost 
    END as new_cost
FROM mytable

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您可以使用

CASE

语句执行类似的操作

CREATE TABLE #tmp (Channel VARCHAR(255), acct_mgmr VARCHAR(255), cost INT)

INSERT INTO #tmp VALUES ('Mobile', 'Mark', 100)
INSERT INTO #tmp VALUES ('desktop', 'James', 200)

SELECT 
    channel,
    acct_mgmr,
    cost, 
    cost * (1 - CASE 
                    WHEN Channel = 'Mobile' AND acct_mgmr = 'Mark' THEN 0.08
                    WHEN Channel = 'Desktop' AND acct_mgmr = 'James' THEN 0.05
                END

    ) AS ModifiedCost
FROM #tmp

DROP TABLE #tmp

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我一点也不懂。请提供一些示例数据并显示预期结果。