帶有3種替代方法的SQL IF語句

Question

嗨，我真的可以使用一些幫助來編寫這個IF語句！我設法滿足2個條件，不知道3rd（計算）如何適合。這是僞代碼中的計算;

IF Producer_Type = 'Oil', Unallocated OIL&GAS = UnallocatedLossesOIL 
IF Producer_Type = 'Gas', Unallocated OIL&GAS = UnallocatedLossesGAS 
ELSE Unallocated OIL GAS = UnallocatedLossesOIL(MPPOil ÷ (MPPOil + MPPGas)) + 
UnallocatedLossesGAS(MPPGas ÷ (MPPOil + MPPGas)) 

這是我的代碼：

SELECT qb1.CompanyName, qb1.AssetName, qb1.Year, 
IIf(qb1.Producer_Type='Oil',qb1.DatapointValue, qb2.DatapointValue) AS UnallocatedOilGas 
FROM PEBaseQuery AS qb1 INNER JOIN PEBaseQuery AS qb2 ON qb1.Assetname=qb2.AssetName 
WHERE qb1.DatapointID=2026 And qb2.DatapointID=2027; 

凡2026 DatapointID是UnallocatedLossesOIL和2027 UnallocatedLossesGAS。該計算需要參考MPPOil和MPPGas值（與特定公司/資產/年相關，這是兩個單獨查詢的結果...任何幫助將非常感謝！對不起，如果這一些沒有意義..

Answer 1

如何嵌套如果條件我的意思是，如果多數民衆贊成可能的，這應該工作：？

SELECT qb1.CompanyName, qb1.AssetName, qb1.Year, 
IIf(qb1.Producer_Type='Oil', qb1.DatapointValue, 
    IIF(qb1.Producer_Type='Gas', qb2.DatapointValue, 
    qb1.DatapointValue * (MPPOil/(MPPOil + MPPGas)) + 
    qb2.DatapointValue * (MPPGas/(MPPOil + MPPGas)))) AS UnallocatedOilGas 
FROM PEBaseQuery AS qb1 INNER JOIN PEBaseQuery AS qb2 ON qb1.Assetname=qb2.AssetName 
WHERE qb1.DatapointID=2026 And qb2.DatapointID=2027; 

關於MPPGas和MPPOil的價值觀，我不知道在哪裏可以找到他們，所以離開了他們，因爲他們是 我希望這可以工作。