MongoDB $lte 运算符

2024 年 9 月 6 日 | 3 分钟阅读

MongoDB 中的 $lte 运算符是什么?

MongoDB 提供了各种比较查询运算符。 $lte(小于等于)运算符是其中一个运算符。 $lte 运算符用于选择字段值小于或等于(即 <=)给定值的文档。 您可以根据您的要求在更新、查找等方法中使用此运算符。

$lte 运算符的语法

示例

在下面的示例中,我们将使用

>db.employee.find()
        {
                "_id" : 1,
                "name" : "John",
                "father_name" : "Thomas",
                "department" : "Contain Writting",
                "experience" : 2,
                "mobile_no" : 9856321478,
                "gender" : "Male",
                "salary" : 22000,
                "age" : 26
        }
        {
                "_id" : 2,
                "name" : "William",
                "father_name" : "Rebort",
                "department" : "Softwre Tester",
                "experience" : 1,
                "mobile_no" : 7896541478,
                "gender" : "Male",
                "salary" : 20000,
                "age" : 21
        }
        {
                "_id" : 3,
                "name" : "Ava",
                "father_name" : "William",
                "department" : "Marketing manager",
                "experience" : 5,
                "mobile_no" : 8789654178,
                "gender" : "Female",
                "salary" : 36500,
                "age" : 25 
        }
        {
                "_id" : 4,
                "name" : "Olivia",
                "father_name" : "Noah",
                "department" : null,
                "experience" : 4,
                "mobile_no" : 9045641478,
                "gender" : "Female",
                "salary" : 30000,
                "age" : 27 
        }
        {
                "_id" : 5,
                "name" : "Elijah",
                "father_name" : "John",
                "department" : "HR",
                "experience" : 0,
                "mobile_no" : 6589741230,
                "gender" : "Male",
                "salary" : 15000,
                "age" : 20
        }
        {
                "_id" : 6,
                "name" : "John",
                "father_name" : "Liam",
                "department" : "Softwre Tester",
                "experience" : 10,
                "mobile_no" : 9014536987,
                "gender" : "Male",
                "salary" : 55000,
                "age" : 30 
        }

示例 1:使用 $lte 运算符

在此示例中,我们正在寻找工资等级小于或等于 30000 的文档。

输出

{
    "_id" : 1,
    "name" : "John",
    "father_name" : "Thomas",
    "department" : "Contain Writting",
    "experience" : 2,
    "mobile_no" : 9856321478,
    "gender" : "Male",
    "salary" : 22000,
    "age" : 26
}
{
    "_id" : 2,
    "name" : "William",
    "father_name" : "Rebort",
    "department" : "Softwre Tester",
    "experience" : 1,
    "mobile_no" : 7896541478,
    "gender" : "Male",
    "salary" : 20000,
    "age" : 21
}
{
    "_id" : 4,
    "name" : "Olivia",
    "father_name" : "Noah",
    "department" : null,
    "experience" : 4,
    "mobile_no" : 9045641478,
    "gender" : "Female",
    "salary" : 30000,
    "age" : 27 
}
{
    "_id" : 5,
    "name" : "Elijah",
    "father_name" : "John",
    "department" : "HR",
    "experience" : 0,
    "mobile_no" : 6589741230,
    "gender" : "Male",
    "salary" : 15000,
    "age" : 20
}

示例 2:另一个字段

在此示例中,我们正在寻找年龄小于或等于 26 的文档。

输出

{
    "_id" : 1,
    "name" : "John",
    "father_name" : "Thomas",
    "department" : "Contain Writting",
    "experience" : 2,
    "mobile_no" : 9856321478,
    "gender" : "Male",
    "salary" : 22000,
    "age" : 26
}
{
    "_id" : 2,
    "name" : "William",
    "father_name" : "Rebort",
    "department" : "Softwre Tester",
    "experience" : 1,
    "mobile_no" : 7896541478,
    "gender" : "Male",
    "salary" : 20000,
    "age" : 21
}
{
    "_id" : 3,
    "name" : "Ava",
    "father_name" : "William",
    "department" : "Marketing manager",
    "experience" : 5,
    "mobile_no" : 8789654178,
    "gender" : "Female",
    "salary" : 36500,
    "age" : 25 
}
{
    "_id" : 5,
    "name" : "Elijah",
    "father_name" : "John",
    "department" : "HR",
    "experience" : 0,
    "mobile_no" : 6589741230,
    "gender" : "Male",
    "salary" : 15000,
    "age" : 20
}

示例 3:使用 $lte 运算符更新值

在此示例中,我们正在更新工作经验小于或等于 3 年的员工的工资字段。

输出

{
    "_id" : 1,
    "name" : "John",
    "father_name" : "Thomas",
    "department" : "Contain Writting",
    "experience" : 2,
    "mobile_no" : 9856321478,
    "gender" : "Male",
    "salary" : 20000,
    "age" : 26
}
{
    "_id" : 2,
    "name" : "William",
    "father_name" : "Rebort",
    "department" : "Softwre Tester",
    "experience" : 1,
    "mobile_no" : 7896541478,
    "gender" : "Male",
    "salary" : 20000,
    "age" : 21
}
{
    "_id" : 5,
    "name" : "Elijah",
    "father_name" : "John",
    "department" : "HR",
    "experience" : 0,
    "mobile_no" : 6589741230,
    "gender" : "Male",
    "salary" : 20000,
    "age" : 20
}