HQL多表連接和SUM（），第（）

Question

Talbes：

Grandpa 
    GP_ID (PK) 
    NAME 

Dad 
    DAD_ID (PK) 
    PG_ID (FK) 

Children 
    C_ID (PK) 
    DAD_ID (FK) 
    MONEY_AMOUNT 
    MONEY_UNIT 

類（此處省略註釋）：

class Grandpa 
{ 
    Long id; 
    String name; 

    Double moneyAmount; // sum of Children's money amount 

    String moneyUnit; // first of Children's money unit. 
} 

class Dad 
{ 
    Long id; 
    Grandpa grandpa; 
} 

class Children 
{ 
    Long id; 
    Dad dad; 

    Double moneyAmount; 
    String moneyUni; 
} 

我想寫一個HQL得到爺爺的對象與總和（grandpa.dad.children.money_amount）和第一（grandpa.dad.children.money_unit）。下面是我的，但它不工作：

select gp, sum(chdn.moneyAmount) as gp.moneyAmount, first(chdn.moneyUnit) as gp.moneyUnit 
from Grandpa gp, Dad dad, Children chdn 
where gp.id =: chdn.dad.grandpa.id 

Answer 1

select gp.id, gp.name, sum(chdn.moneyAmount) as moneyAmount, min(chdn.moneyUnit) as gp.moneyUnit 
from Children chdn, chdn.dad dad, dad.grandpa gp 
groupBy gp.Id 

，並使用aliastobean變壓器伸入爺爺DTO

或者你實現moneyAmount和單位作爲訪問包含兒童集合屬性爸爸，總結在內存中的金額那麼這將是

select gp from Grandpa gp join fetch gp.children dad join fetch dad.children 

但巨大的笛卡爾產品

提防3210