Listado de la etiqueta: Query


“The date is returned as a string or as an object in MongoDB’s date queries. The current date is returned as a string by date query in the mongo console. MongoDB will output the current date as an object of a date, which will be wrapped in an encapsulation assist. The date can be specified as an ISODate string, which is then provided to MongoDB’s new date() method within the defined range. If you’ve ever attempted to save a JavaScript Date object to MongoDB, you’ll notice that MongoDB wraps your date in an odd function called ISODate().

ISODate() allows you to visually portray a date in MongoDB as a String while allowing you to use date queries and indexing. The programmer can analyze date objects quickly and visually by enclosing the ISO date String in a function rather than converting it from a Unix timestamp to a time String.

Today, we’ll explore how to create a MongoDB Date greater than a query to retrieve records based on a timestamp or a date range. Examples of MongoDB date queries will be shown, such as MongoDB date greater than time or date, and so on.

Greater than operator($gt) is among MongoDB’s comparison operators. The greater than $gt operator is then used to discover documents where the value of a field is greater than (>) the value set. Depending on your needs, you can utilize this operator in functions such as locating, updating, and so on.”

Syntax of a Date Greater Than Query

The information below demonstrates how to use this syntax in a collection of data in practice.

db.collection_name.find({
    field_name: {
        $gt: ISODate(«date»),
        $lt: ISODate(«date»)
    }
})

This query returns all entries in the collection with a field name that is greater than or equal to the date passed in the ISODate method but less than or equal to the date returned by the ISODate method. Here $gt denotes the “greater than” symbol, and $lt indicates the “less than” symbol. The preceding steps are simple to follow. There are a few minor changes between these directions, though.

How to Create a Date Greater Than Query MongoDB in Ubuntu 20.04

This section demonstrates how to create a MongoDB date greater than a query that returns records depending on a timestamp. MongoDB date greater than time or date is included in the examples of a date query in MongoDB.

To further understand the concept, let’s create a data collection by inserting the document. The query to create a collection comprising a record is as follows:

First, we have established a database as a “shop” inside the mongo shell. Then, we have given a name to our collection as “Mart” inside the create collection query. As our collection is created, we have used the following query for creating the collection’s document.

In the above figure, we have inserted three documents inside the collection “Mart” with the insertMany query. Instead of inserting a record one at a time, we may use this query to enter a record all at merienda within the specified collection. Then, in the end, the acknowledged statement inserted the ID’s for the documents that show the documents are successfully inserted in the collection “Mart.”

Now, use these documents of the collection against the date greater than the query in the MongoDB shell. Let’s execute this query in the example implemented below.

Example # 1: Find a Record Between Two Dates in MongoDB in Ubuntu 20.04

To find all documents with a field name between two dates, we ran the following query.

We have utilized the find function here, and within the function, we have called a field “date” from the collection “Mart.” We have done a greater than and less than operation on the date field by giving two different ISODate from the collection. From this query, we yield an ISODate greater than the date “2022-03-12T00:00:00Z” and lesser than the date “2022-03-12T00:00:00Z”.

The above query returns the results between the “greater than” ISODate and “less than” ISODate in the following MongoDB snap shell.

Example # 2: Find a Record Greater Than the Specific Date in MongoDB in Ubuntu 20.04

We are using the greater than operator on the specific date to find the date from the document. And from this, we will get a date greater than a specific date in the query. Let’s demonstrate the statement by executing the query in MongoDB.

We have a db.Mart.find query inside which we have specified the date field. The date field has given a “greater than” operator as $gt, and the $gt operator has been assigned with the ISODate “2022-02-12”. If the ISODate is greater than this date from the document, it only displays those documents.

The above query returns the two documents which have the ISODate date greater than the date given to the $gt operator.

Example # 3: Retrieve a Record Based on a Date in MongoDB in Ubuntu 20.04

We are retrieving the record from the collection, where the date field matches the ISODate given in the query. We have utilized the greater than equal to operator. Let’s consider the example of using MongoDB to give a query based on the current date.

In the above query, we have a date field inside the find function. The date is using the greater than equal to operator “$gte” and specified the $gte operator the ISODate with utilizing the new keyword. After that pretty method is used at the end of the query to display the results in an easier format.

The date returned by the above query is shown in the following snapshot.

Conclusion

This article is based upon a date greater than the query in MongoDB. We have begun with a brief introduction where the Date function and the $gt operator in MongoDB are briefly explained. Also, we have shown the syntax of a date greater than the query. This article clearly shows you using the Date() method. The $gt and the $gte queries are also described in detail with examples. The use of code snippets to explain well how to retrieve a query-dependent date is also demonstrated.



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MongoDB filter aggregation was introduced in version 3.2. It is used to choose a subset of an array and provide the result based on criteria. The filter operator returns an array of entries that fit the provided criterion in the order they were found. When using the filter operator in MongoDB, we must provide the input, as and cond as arguments. Input and cond are required parameters, however “as” is optional. We must use the $ sign before the filter keyword when we use the filter operator in MongoDB.

Syntax of the Filter Query MongoDB in Ubuntu 20.04?

The $filter operator provides an array with just those elements in the flamante order that match the condition. Mentioned below is the syntax of $filter:

{ $filter: { input: <array_field>, as: <string>, cond: <expression> } }

  • filter: The $filter operator is used to provide a result that meets certain criteria. In MongoDB, we used the filter operator to filter the results based on the criterion we specified in the query.
  • input: This is an array resolution expression. We managed to pass the array field as an input parameter to filter the records. Before we use the input field parameter in the filter operator, we must use the $ sign.
  • as: It’s a filter operator argument that’s optional. This is the field’s name which was utilized as an element in the input array. This parameter is of the string type in the filter operator. Using the “as” keyword, this expression accesses each element in an input array.
  • cond: This option determines where the value from the generated array should be included. This parameter is of the expression type in the filter operator. The values from the given collection were filtered using expression. We can use numerous conditional operators to filter data from array elements.

How the Filter Query works in MongoDB in Ubuntu 20.04:

A MongoDB $filter operator is used to filter documents from an array based on a condition that we defined in our query. Based on the given condition, returns a subset of an array. Only those array entries that satisfy the requirements are returned. The elements are reassembled in the same arrangement as before.

Let’s look at some instances to help you understand what we are discussing. As we proceed through the article, we would like you to try the examples in the mongo shell. We start by creating a database collection that utilizes throughout the article.

Here, we have defined a collection of the database as “candidates” by using the MongoDB shell. For this collection, we have the id, name, and marks field defined. We have inserted seven documents at the same time by using the insertMany query.

The collection “candidates” is invoking the find function as in the above query. Then, the recorded document displays the field and its corresponding values. Note that in the field “marks”, the array is defined with some random values.

Example 1:Using the $filter operator in MongoDB in Ubuntu 20.04:

The $filter operator is used to filter the array members in the field “marks” from the given collection in the following example:

We have utilized the aggregate query on the collection of “candidates”. Inside this query, we have the $match operator which is used to filter the document by the id. We have assigned the id field a $in operator. The $in operator finds documents where the value of id equals any value in the provided array. Then, the $filter operator is passed the input argument and sets its value “$marks”. The “as” parameter is also used which returns the field name “marks”. Then, we have specified the cond parameter that uses the greater than operator on the field “$$marks”.

By following the above query, the result we got is shown in the figure with the new field name highmarks.

Example 2:Using the $filter operator for an empty array in MongoDB in Ubuntu 20.04:

When one of our collection documents has an empty array, the filter operator returns an empty array set, as can be seen here:

Within the $match we have specified the id that has the $in operator which returns id “7” from the collection as we have given “7” inside an array. Then, the $filter query has provided the collection field “marks” which returns an empty array because no value is stored inside the “marks” field of id “7”.

The result of the filter operator has an empty set of the document here.

Example 3: Using the $filter operator for the wrong type in MongoDB in Ubuntu 20.04:

If we try to use the $filter on a field that doesn’t have an array, we will get an error. The following is the demonstration of this statement.

We have given a field “name” from the document whose id is “5” inside the $filter operator. In the parameter cond of $filter, we have the $eq operator which takes the field “$name” and matches the string value defined to it.

When we run the above query, the error message shows that the type must be an array in the $filter operator as seen in the figure.

Example 4: Using the $filter operator with the $this variable in MongoDB in Ubuntu 20.04:

We used the “as” parameter to give the variable a name in the earlier cases. The as parameter is optional. If we set this field blank, the variable name will be “this” by default.

Here, we have specified the array in $in operator which selects the id fields from the documents of the given collection within the $match. Then, the $filter has the two-parameter, input and cond. The cond parameter has the greater than operator which retrieves the marks greater than 65. We haven’t used them as a parameter, instead we utilized the $$this field name.

Hence by using $$this to reference the field, we got the same results as from the “as”. The output is satisfied with the $match condition and the $filter condition seen in the picture.

Conclusion:

This is a MongoDB Filter guide. In this article, we have gone through the definition, syntax, and how filters function in MongoDB. Examples and code implementation are also provided. The array field’s elements are filtered using the MongoDB filter operator. To retrieve data from array elements, we have utilized several conditions such as $gt, $lt, $gte, and $lte.



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