连接4个表的数据库联接

SELECT Investment_Type
FROM Investment_Type
WHERE idInvestment_Type IN (
    SELECT idInvestment_Type
    FROM Portfolio
    WHERE idPortfolio IN (
         SELECT idPortfolio 
         FROM Client_Portfolio
         WHERE idClient IN ( SELECT idClient FROM Client)
         )
   )

尝试下面提到的查询:

SELECT  IT.Investment_Type
FROM
Client_portFolio CF 
LEFT JOIN portfolio P ON (CF.idPorFolio = P.idPorFolio)
LEFT JOIN investment_type IT ON(P.idInvestmentType =IT.idInvestmentType)
WHERE CF.idClient = <ClientId>