To add a value to the top of an array in MongoDB, you can use unshift() − , The above syntax will add the value to the top of an array in MongoDB. Let us first create an array of strings − , This will produce the following output − , Following is the query to add to the top of an array in MongoDB. Here, we will add “MongoDB” to top of an array using unshift() &.....

You can use getTime() for this. Following is the syntax − , Convert ISODate to numerical value − , Following is the query to convert ISODate to numerical value − , This will produce the following output − , Let us verify that it is a correct numerical value for ISODate or not. Following is the query to get correct ISODate whenever we apply above numeric value −.....

You can use aggregate framework to create an alias. Let us first create a collection with documents − , Following is the query to display all documents from the collection with the help of find() method − , This will produce the following output − , Following is the query to create alias in a query − , This will produce the following output − ,

The group is a type of method in MongoDB. It shouldn’t be created as a collection name. Even if you created it, you can easily remove it using getCollection('group').drop();). Let us first create a collection with documents − , Following is the query to display all documents from the collection with the help of find() method − , This will produce the following output &minu.....

You can use $pull operator for this. Let us first create a collection with documents − , Following is the query to display all documents from the collection with the help of find() method − , This will produce the following output − , Following is the query to remove null element from MongoDB array − , Let us check the null has been removed or not − , This will.....

Too return a specific field, use the find() method in MongoDB. Let us first create a collection with documents − , Following is the query to display all documents from the collection with the help of find() method − , This will produce the following output − , Following is the query to return specific field. Here, we are returning the field “LastName” − ,.....

Let us first create a table − , Insert records in the table using insert command − , Display records from the table using select command − , This will produce the following output − , Following is the query to select the column where value = one or value = two, etc i.e. UserAge in our table with different ages − , This will produce the following output − ,

You can use INFORMATION_SCHEMA.TABLES and AVG_ROW_LENGTH to query average row length in MySQL − , Let us first create a table − , Insert records in the table using insert command − , Display records from the table using select command − , This will produce the following output − , Query average row length in MySQL − , This will produce the following outpu.....

You can use LPAD() from MySQL for this. Let us first create a table − , Insert records in the table using insert command − , Display records from the table using select command − , This will produce the following output − , Following is the query to align a column right-adjusted − , This will produce the following output − ,

You need to use backticks around the table name where the table name has blank space. Let us first create a table.  Here, we have used backtick − , Insert records in the table using insert command − , Display records from the table using select command − Following is the query to select data from a table where the table name has blank spaces in it − , This will .....