您可以使用两种选项。

选项1

您可以添加

  OrderItem {
 BigDecimal soldPrice 
整数soldQuantity 
 BigDecimal totalPrice 

 static mapping = {
 totalPrice formula：sold_price * sold_quantity
} 

 static belongsTo = [order：Order， item：Item] 

} 
 

现在您的标准查询可以包含

 预测{
 sum（totalPrice）
} 
 

不仅如此，您可以使用动态查找器查询它 OrderItem.findAllByTotalPriceGreaterThan（20.00） as以及简单访问 printlnfin价格是$ {orderInstance.totalPrice} 。我们发现这真的很棒，但有时候你想在OrderItem被保存之前得到totalPrice，所以我们通常写一个简单的（不干的）getter

  BigDecimal getTotalPrice（）{
 totalPrice？：（soldPrice&&soldQuantity）？ soldPrice * soldQuantity：null 
} 
 

但是，如果您需要，您只需要这样的事情

$ b

选项2

在公式映射之前，我们用于下载到Hibernate Criteria API并使用sqlprojection投影作为我们的条件查询的一部分。

 预测{
作为字符串[]，
 [Hibernate.LONG]，作为类型[]的addProjectionToList（作为totalPrice的
sum（sold_price * sold_quantity），
 [totalPrice]） 
），sumProjection）
} 
 

我认为重要的是要注意，在公式和sql投影中，使用数据库中的列名和数据库特定的sum语法。

p>

I need to get a sum of all items sold per order per store. I am running a sum() on expression using executeQuery(). It works fine as shown below but I wanted to know if there is a better, groovier way to do it.

StoreService {
  static transactional = false

  def getTotalOrders(def store) {
    return Store.executeQuery("select sum(a.soldQuantity * a.soldPrice) as total 
             from OrderItem a inner join a.order b inner join b.store c 
             where c= :store", [store: store]).get(0)
  }
}

Store {
  transient storeService

  def getTotalSales() {
    storeService.getTotalSales()
  }

  static hasMany = [items: Item]
  // no hasMany to Order
}

Item {
  static belongsTo = [store: Store]
  // no hasMany to OrderItem
}


Order {
  static hasMany = [orderItems: OrderItem]
  static belongsTo = [store: Store]
}


OrderItem {

  BigDecimal soldPrice
  Integer soldQuantity

  static belongsTo = [order: Order, item: Item]

}

I think withCriteria() would be easier to read but I couldn't figure out how to do it with expressions within sum() wouldn't take for obvious reasons.

projections {
  sum("soldPrice * soldQuantity")
}

Thanks

There are two options you can go with.

Option 1

You can add a formula mapping to your domain class then query it directly.

OrderItem {
  BigDecimal soldPrice
  Integer soldQuantity
  BigDecimal totalPrice

  static mapping = {
    totalPrice formula: "sold_price * sold_quantity"
  }

  static belongsTo = [order: Order, item: Item]

}

Now your criteria query can just contain

projections {
    sum("totalPrice")
}

Not only that but you can query it with dynamic finders OrderItem.findAllByTotalPriceGreaterThan(20.00) as well as simple access println "The final price is ${orderInstance.totalPrice}. We find this really nifty however there are times when you would want to get totalPrice before the OrderItem has been persisted so we usually write a simple(Not DRY) getter

BigDecimal getTotalPrice() {
    totalPrice ?: (soldPrice && soldQuantity) ? soldPrice * soldQuantity : null
}

But you only need this sort of thing if you require totalPrice before it has been persisted.

Option 2

Before formula mappings we used to drop down to the Hibernate Criteria API and use a sqlProjection Projection as part of our criteria query.

projections {
    addProjectionToList(Projections.sqlProjection(
            "sum(sold_price * sold_quantity) as totalPrice",
            ["totalPrice"] as String[], 
            [Hibernate.LONG] as Type[],
        ), "sumProjection")
 }

Note

I think it is important to note that in both the formula and the sql projection, use the column names in the database and your database specific sum syntax.