关于 grails “createCriteria”的新手问题

Question

我是 Grails 标准构建器的新手，有人可以解释以下是什么意思吗？

def c = Account.createCriteria()
         def results = c {

             like("holderFirstName", "Fred%")
             and {
                 between("balance", 500, 1000)
                 eq("branch", "London")
             }
             maxResults(10)
             order("holderLastName", "desc")
         }

是不是意味着

• Select * from account where holderFirstName like 'fred%' and (balance between 500 and 1000 **and** branch='london ')
• Select * from account where holderFirstName like 'fred%' and (balance between 500 and 1000 **or** branch='london ')

如果我想同时使用“或”和“和”，我该怎么做？

Answer 1

您的示例将执行为：

select * from account 
where holderFirstName like 'Fred%' 
and balance between 500 and 1000 
and branch = 'London'

所有顶级条件都被暗示为“与”在一起。 您可以创建与以下相同的条件：

def c = Account.createCriteria()
def results = c {
    like("holderFirstName", "Fred%")
    between("balance", 500, 1000)
    eq("branch", "London")
    maxResults(10)
    order("holderLastName", "desc")
}

要获得第二个查询，请使用此标准：

def c = Account.createCriteria()
def results = c {
    like("holderFirstName", "Fred%")
    or {
        between("balance", 500, 1000)
        eq("branch", London")
    }
    maxResults(10)
    order("holderLastName", "desc")
}

嵌套您的and / or闭包以获得更复杂的标准。

Answer 2

您当前的标准在平衡和分支两个条件中意味着“和”。 所以

Select * from account where holderFirstName like 'fred%' and (balance between 500 and 1000 and branch='london') 是正确的，只是它将容纳最多 10 个结果，并将根据 "holderLastName" 降序排序.

要同时使用and和or ，您还需要在标准中指定or块，因此您的标准看起来像

Account.createCriteria()
         def results = c {

             like("holderFirstName", "Fred%")
             and {
                 between("balance", 500, 1000)
                 eq("branch", "London")
             }
             or{
                 eq("prop1", prop1)
                 eq("prop2",prop2)
             }
             maxResults(10)
             order("holderLastName", "desc")
         }

在此标准中，平衡条件和分支条件之间存在and 。 也是 prop1 和 prop2 之间的or