我在聚合管道阶段列出了一些文档,如下所示:
[{
obj1:{code:"123"},
obj2:{code:"654"},
obj3:{code:"abc"},
obj4:{code:"xyz"},
type:"obj1",
},{
obj1:{code:"123"},
obj2:{code:"654"},
obj3:{code:"abc"},
obj4:{code:"xyz"},
type:"obj2",
},{
obj1:{code:"123"},
obj2:{code:"654"},
obj3:{code:"abc"},
obj4:{code:"xyz"},
type:"obj4",
}]
在相同的聚合管道中,如果不使用$Switch用例,我们是否有可能在每个对象中为其在$project阶段的相应类型值投影代码字段?
结果应该是:
[{
obj1:{code:"123"},
obj2:{code:"654"},
obj3:{code:"abc"},
obj4:{code:"xyz"},
type:"obj1",
code:$type.code // should return "123"
},{
obj1:{code:"123"},
obj2:{code:"654"},
obj3:{code:"abc"},
obj4:{code:"xyz"},
type:"obj2",
code:$type.code // should return "654"
},{
obj1:{code:"123"},
obj2:{code:"654"},
obj3:{code:"abc"},
obj4:{code:"xyz"},
type:"obj4",
code:$type.code // should return "xyz"
}]
提前谢谢你.