mongodb的Query的Criteria 的gte方法为什么只能筛选大于的

`gte` 方法是 MongoDB 查询语言中的一个操作符，表示“大于等于”，用于比较一个字段的值是否大于或等于指定值。因此，它不仅可以筛选大于指定值的文档，还可以包含等于指定值的文档。

如果您要筛选小于等于指定值的文档，可以使用 `lte` 方法，它表示“小于等于”。如果您要筛选小于指定值的文档，可以使用 `lt` 方法，它表示“小于”。同样地，如果您要筛选大于指定值的文档，可以使用 `gt` 方法，它表示“大于”。

例如，以下代码将返回 `age` 字段大于等于 18 的所有文档：

db.collection.find({ age: { $gte: 18 } })

希望能帮助到您！

相关问题

public int findCount(Class<T> tClass, Date startTime,Date endTime){ Criteria where = new Criteria().andOperator(Criteria.where("clickTime").gte(startTime),Criteria.where("clickTime").lte(endTime)); } mongodb查询记录数补全代码

可以使用MongoTemplate来执行查询并获取记录数，例如：

@Autowired
private MongoTemplate mongoTemplate;

public long findCount(Class<T> tClass, Date startTime, Date endTime) {
    Criteria where = new Criteria().andOperator(
            Criteria.where("clickTime").gte(startTime),
            Criteria.where("clickTime").lte(endTime)
    );
    Query query = Query.query(where);
    long count = mongoTemplate.count(query, tClass);
    return count;
}

其中，Query对象用于封装查询条件，mongoTemplate.count()方法返回符合条件的记录数。注意要将startTime和endTime转成MongoDB的Date类型再进行比较。

mongodb find

The MongoDB `find()` method is used to retrieve documents from a collection based on certain criteria. It takes in a query object as a parameter, which specifies the conditions that the documents must meet to be returned.

The basic syntax of the `find()` method is as follows:

db.collection.find(query, projection)

Here, `collection` is the name of the collection to search in, `query` is the query object that specifies the conditions for matching documents, and `projection` is an optional parameter that specifies which fields to include or exclude in the returned documents.

For example, to find all documents in a collection named `users` where the `age` field is greater than or equal to 18, we can use the following query:

db.users.find({ age: { $gte: 18 } })

This will return all documents in the `users` collection where the `age` field is greater than or equal to 18.

We can also use other operators like `$lt` (less than), `$gt` (greater than), `$ne` (not equal), etc. to specify more complex queries. Additionally, we can use the `projection` parameter to specify which fields to include or exclude in the returned documents. For example, to exclude the `_id` field from the returned documents, we can use the following query:

db.users.find({ age: { $gte: 18 } }, { _id: 0 })