MongoDB $not 运算符

MongoDB $not 运算符 介绍

MongoDB 提供了多种逻辑查询运算符。$not 运算符就是这些运算符之一。它类似于编程中的逻辑非运算符。$not 运算符用于对指定的表达式执行逻辑“NOT 运算”。您可以将它与任何其他查询表达式一起使用，例如等于 ($eq)、大于 ($gt) 或小于 ($lt)。

$not 运算符可以与正则表达式一起使用。它只选择或检索那些与给定运算符表达式不匹配的文档。用户可以根据需要在 find()、update() 等方法中使用此运算符。

MongoDB $not 运算符 语句

{ field: { $not: { operator-expression } } }  

MongoDB $not 运算符 例子

在以下示例中，我们正在使用：

Database: Yiidian
Collection: student  
Document: Six documents that contain the details of the students  

[  
        {  
                "std_name" : "Jack",  
                "sex" : "Male",  
                "class" : "VI",  
                "age" : 11,  
                "Total_marks" : 303  
                "Result" : "Pass"  
        },  
        {  
                "std_name" : "Jenny",  
                "sex" : "Female",  
                "class" : "VI",  
                "age" : 13,  
                "Total_marks" : 800  
                "Result" : "Pass"  
        },  
        {  
                "std_name" : "Thomas",  
                "sex" : "Male",  
                "class" : "V",  
                "age" : 11,  
                " Total_marks" : 200  
                " Result" : "Fail"  
        },  
        {  
                "std_name" : "Lassy",  
                "sex" : "Female",  
                "class" : "X",  
                "age" : 17,  
                "Total_marks" : 550  
                "Result" : "Pass"  
        },  
        {  
                "std_name" : "Mia",  
                "sex" : "Female",  
                "class" : "X",  
                "age" : 19,  
                " Total_marks" : 350  
                "Result" : "Pass"  
       },  
       {  
                "std_name" : "Mike,  
                "sex" : "Male",  
                "class" : "V",  
                "age" : 16,  
                "Total_marks" : 700  
                "Result" : "Pass"  
        }  
]  

示例 1：MongoDB 逻辑 $not 运算符（至少）：

在此示例中，我们仅检索“Total_marks”至少为 400 的学生的数据。

效果类似于下面的SQL语句：

SELECT *   
FROM student   
WHERE Total_marks >= 400;  

输出结果为：

>db.student.find({"Total_marks" : {$not: {$lt : 400}}}).pretty()
{      
                "_Id" : ObjectId("4565d4cd85d4f1vf6345612"),    
                "std_name" : "Jenny",
                "sex" : "Female",
                "class" : "VI",
                "age" : 13,
                "Total_marks" : 800
                "Result" : "Pass"
}
{
                "_Id" : ObjectId("4565d4cd85d4f1vf6345665"),
                "std_name" : "Lassy",
                "sex" : "Female",
                "class" : "X",
                "age" : 17,
                "Total_marks" : 550
                "Result" : "Pass"
}
{
                "_Id" : ObjectId("4565d4cd85d4f1vf6345756"),
                "std_name" : "Mike,
                "sex" : "Male",
                "class" : "V",
                "age" : 16,
                "Total_marks" : 700
                "Result" : "Pass"
}

示例 2：MongoDB 逻辑 $not 运算符（不大于）：

在这个例子中，我们只检索“年龄”不大于 12 的学生的数据。

db.student.find({ "age"  : {$ not : {$gt : 12}}}).pretty()   

输出结果为：

>db.student.find({"age" : {$not: {$gt : 12}}}).pretty()
{
                "_Id" : ObjectId("4565d4cd85d4f545ffg43df7"),
                "std_name" : "Jack",
                "sex" : "Male",
                "class" : "VI",
                "age" : 11,
                "Total_marks" : 303
                "Result" : "Pass"
} 
{
                "_Id" : ObjectId("4565d4cd85d4f545ffg43df7"),
                "std_name" : "Thomas",
                "sex" : "Male",
                "class" : "V",
                "age" : 11,
                " Total_marks" : 200
                " Result" : "Fail"
}

示例 3：MongoDB 逻辑 $not 运算符（不等于）：

在此示例中，我们仅检索“age”不等于 11 的学生的数据。

db.student.find({ "age"  : {$ not : {$eq : 11}}}).pretty()  

>db.student.find({"age" : {$not: {$eq : 11}}}).pretty()
{
               "_Id" : ObjectId("4565d4cd85d45d4dgf1fd5f4"),
               "std_name" : "Jenny",
                "sex" : "Female",
                "class" : "VI",
                "age" : 13,
                "Total_marks" : 800
                "Result" : "Pass"
}
{
                "_Id" : ObjectId("4565d4cd85d45d4dgf1fd55s"),
                "std_name" : "Lassy",
                "sex" : "Female",
                "class" : "X",
                "age" : 17,
                "Total_marks" : 550
                "Result" : "Pass"
}
{
                "_Id" : ObjectId("4565d4cd85d45d4d85331531"),
                "std_name" : "Mia",
                "sex" : "Female",
                "class" : "X",
                "age" : 19,
                " Total_marks" : 350
                "Result" : "Pass"
}
{
                "_Id" : ObjectId("4565d4cd85d45d4456c53154"),
                "std_name" : "Mike,
                "sex" : "Male",
                "class" : "V",
                "age" : 16,
                "Total_marks" : 700
                "Result" : "Pass"
}