grails - 在GORM中按周/月/年分组

Question

我有一个域类(最小化):-

class Expense {
    Date dateOfExpense
    int amount
}

我试图获取按支出日期的周/月/年分组的金额总和。
在grails doc http://grails.org/doc/latest/guide/GORM.html中引用“sqlGroupProjection”方法，

我尝试使用以下代码:-

def results = c {
    between("dateOfExpense", fromDate, toDate)              
    projections {
         sqlGroupProjection 'dateOfExpense,sum(amount) as summed',       
        'MONTH(dateOfExpense)',['date','summed'],[DATE,NUMBER]                  
    }
}

引发异常:

 No such property: DATE for class: grails.orm.HibernateCriteriaBuilder. Stacktrace follows:
 Message: No such property: DATE for class: grails.orm.HibernateCriteriaBuilder

请提出一种使用sqlGroupProjection方法的方法

Answer 1

在域类中分别为周，月和年创建三个新的数字字段。这些字段不会映射到表中的列。

为这三个字段提供静态映射。

static mapping = {
     //provide the exact column name of the date field
     week formula('WEEK(DATE_OF_EXPENSE)')    
     month formula('MONTH(DATE_OF_EXPENSE)')
     year formula ('YEAR(DATE_OF_EXPENSE)')
}

现在我们可以使用

def results = c.list {
  between("dateOfExpense", fromDate, toDate) 
  projections {
    switch(groupBy){
        case "week":
           groupProperty('year')
           groupProperty('month')
           groupProperty('week') 
        break;
        case "month"
           groupProperty('year')
           groupProperty('month')
        break;
        case "year":
           groupProperty('year')
        break;
    }        
    sum('amount')
  }
}