zoukankan      html  css  js  c++  java
  • mongo-go-driver mongo filter

    and or 判断数组为空

    rd:=bson.M{"num":"1","$or":[]bson.M{{"$where":"this.logo.length>0"},{"$where":"this.ziliao.length>0"}}}

     

    mongo-go-driver: nested OR/AND query filter

    I try to create a MongoDB query filter with the nested operators (OR/AND/...). But lib requires to create a bson.D and pass bson.E elements into it. If I need to have OR/AND inside AND/OR - I need to put bson.M + bson.D inside bson.D like this:

    filter := bson.M{"$and": bson.D{{"p", 10}, bson.M{"$or": bson.D{{"s", 30}, {"a", 1}}}}}
    

    .. and of course it doesn't work: cannot use primitive.M literal (type primitive.M) as type primitive.E in slice literal. Probably the same problem will happen if later I try to use a ... in [] logics inside a bson.D

    How do I create such nested queries in Go and official MongoDB driver?

     

    What matters is that $or requires an array, which is bson.A , Also $and is the default, you don't have to indicate that.

    Your filter can be defined like this:

    filter := bson.D{
        {"p", 10},
        {"$or", bson.A{
            bson.D{{"s", 30}},
            bson.D{{"a", 10}},
        }},
    }
    

    You may also use this:

    filter = bson.D{
        {"p", 10},
        {"$or", bson.A{
            bson.M{"s": 30},
            bson.M{"a": 10},
        }},
    }
    

    Or this:

    filter := bson.M{
        "p": 10,
        "$or": bson.A{
            bson.M{"s": 30},
            bson.M{"a": 10},
        },
    }
  • 相关阅读:
    try catch finally中return的执行顺序
    多线程和同步
    orecle常用函数
    java如何调用接口 2
    orecle 函数
    ==和equals在比较字符串时候的区别
    orecle触发器
    java实现同步的方法
    java如何调用接口
    SMM+maven下的log4j配置打印sql
  • 原文地址:https://www.cnblogs.com/eiguleo/p/14070146.html
Copyright © 2011-2022 走看看