触发器：使用条件语句

Question

请看下面的查询

DELIMITER $$
CREATE TRIGGER `Ongoing_Portfolio_AINS` AFTER INSERT ON `Ongoing_Portfolio` FOR EACH ROW
BEGIN
    UPDATE Portfolio
    SET Invest_Amount = New.Investment_Value,
    Cash_Value = New.Cash_Value,
    Date_Of_Last_Update = New.Updated_Date
    WHERE idPortfolio = New.idPortfolio;

    INSERT INTO Ongoing_Fees (currentDate, Ongoing_Gross_Fee,Ongoing_Vat, Updated_Date, idPortfolio)
    SELECT current_timestamp,
    (New.Investment_Value+New.Cash_Value)*(p.Ongoing_Gross_Fee/100),
    (((New.Investment_Value+New.Cash_Value)*(p.Ongoing_Gross_Fee/100))*(p.Ongoing_eee_Fee/100))*0.2,
    New.Updated_Date,
    New.idPortfolio
    FROM Portfolio p
    WHERE p.idPortfolio = New.idPortfolio;
END;

但是在这里，Ongoing_Vat 仅适用于p.Vat = true，否则为NULL。如何添加此条件语句以便正确计算 Ongoing_Vat？

Answer 1

感谢@Twelfth 在 cmets 中的回答，代码格式如下：

INSERT INTO Ongoing_Fees (currentDate, Ongoing_Gross_Fee,Ongoing_Vat, Updated_Date, idPortfolio)
SELECT 
  current_timestamp as currentDate,
  (New.Investment_Value+New.Cash_Value)*(p.Ongoing_Gross_Fee/100) as Ongoing_Gross_Fee,
  case when p.vat = true then (((New.Investment_Value+New.Cash_Value)*(p.Ongoing_Gross_Fee/100))*(p.Ongoing_eee_Fee/100))*0.2 
    else null end as Ongoing_Vat,
  New.Updated_Date as Updated_Date,
  New.idPortfolio as idPortfolio
FROM 
  Portfolio p
WHERE 
  p.idPortfolio = New.idPortfolio;