grails-使用联合表在查询中获取列

我有这样的标准：

            def e = Equipment.createCriteria()
            def equipmentInstanceList = e.list {
                createAlias "rentals", "r", org.hibernate.sql.JoinType.LEFT_OUTER_JOIN
                projections {
                    property('name')
                    property('r.status')
                    property('r.dateRented')
                    property('r.dateReturned')
                }
            }

我的想法是，它将返回二维列表。如前所述。据我所知，第一个列表是所选项目的列表，第二个列表是项目列的列表。我的问题是

如何获取所有选定的项目？例如：

def list = equipmentInstanceList.[all] //supposed to get all the selected items
def a =  equipmentInstanceList[1] //will only get the 1st item in 1st list

def a = equipmentInstanceList[1].status //supposed to get the status column in 2nd list

def a = equipmentInstanceList[1].status //supposed to get the status column in 2nd list

如何访问第二个列表中的特定列？例如：

def list = equipmentInstanceList.[all] //supposed to get all the selected items
def a =  equipmentInstanceList[1] //will only get the 1st item in 1st list

def a = equipmentInstanceList[1].status //supposed to get the status column in 2nd list

def a = equipmentInstanceList[1].status //supposed to get the status column in 2nd list

编辑：

此查询的结果与上述条件相同

def equipmentForRent = Equipment.executeQuery("SELECT e.name, r.status, r.dateRented, r.dateReturned FROM ers.Equipment e LEFT JOIN e.rentals r")

我仍在尝试获取

equipmentForRent

中的列。到目前为止我正在尝试的

each.equipmentForRent { e -> println e.dateReturned }

仍然会出现此错误：

Exception evaluating property 'dateRented' for java.util.Arrays$ArrayList, Reason: groovy.lang.MissingPropertyException: No such property: dateRented for class: java.lang.String

为什么它与此查询不同：

def rentalTest = Rental.executeQuery("FROM Rental")
println rentalTest.status //no error, returns the status column from rental

---

有人吗？

您一次提出了两个问题： 很快：

如何获取所有选定的项目？例如：

def list = equipmentInstanceList.[all] //supposed to get all the selected items
def a =  equipmentInstanceList[1] //will only get the 1st item in 1st list

def a = equipmentInstanceList[1].status //supposed to get the status column in 2nd list

def a = equipmentInstanceList[1].status //supposed to get the status column in 2nd list

如何访问第二个列表中的特定列？例如：

def list = equipmentInstanceList.[all] //supposed to get all the selected items
def a =  equipmentInstanceList[1] //will only get the 1st item in 1st list

def a = equipmentInstanceList[1].status //supposed to get the status column in 2nd list

def a = equipmentInstanceList[1].status //supposed to get the status column in 2nd list

要获得第二名：

def a = equipmentInstanceList[2].status // this now points to 2nd element status

但这些都不是空安全的，可能会导致问题。 要使用索引遍历元素，请执行以下操作：

equipmentInstanceList?.eachWithIndex{  e,i->
  println "-- $i is index $e is element"
 }

您已尝试在HQL中执行sql查询

def equipmentForRent = Equipment.executeQuery("SELECT e.name, r.status, r.dateRented, r.dateReturned FROM ers.Equipment e LEFT JOIN e.rentals r")

尝试从表中换行选择新映射（项），如图所示

def equipmentForRent = Equipment.executeQuery("SELECT new map(e.name as name, r.status as status, r.dateRented as dateRented, r.dateReturned as dateReturned) FROM Equipment e LEFT JOIN e.rentals r")

---

您建议的解决方案中的地图键将作为真实列，对吗？对不起，我提出了一个毫无意义的问题。非常感谢您的帮助查询中的

新映射

方法解决了我的问题没有问题我想您的第二条评论意味着您理解它。