You can use $not operator along with $type for this. Let us first create a collection with documents −
> db.highestNumericValueOfAColumnDemo.insertOne(
... {
... "StudentName": "John",
... "StudentMathMarks":69
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cba05727219729fde21ddb1")
}
> db.highestNumericValueOfAColumnDemo.insertOne(
... {
... "StudentName": "Carol",
... "StudentMathMarks":"89"
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cba059d7219729fde21ddb2")
}
> db.highestNumericValueOfAColumnDemo.insertOne(
... {
... "StudentName": "Chris",
... "StudentMathMarks":82
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cba059d7219729fde21ddb3")
}
> db.highestNumericValueOfAColumnDemo.insertOne(
... {
... "StudentName": "John",
... "StudentMathMarks":"100"
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cba059d7219729fde21ddb4")
}Following is the query to display all documents from the collection with the help of find() method −
> db.highestNumericValueOfAColumnDemo.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5cba05727219729fde21ddb1"),
"StudentName" : "John",
"StudentMathMarks" : 69
}
{
"_id" : ObjectId("5cba059d7219729fde21ddb2"),
"StudentName" : "Carol",
"StudentMathMarks" : "89"
}
{
"_id" : ObjectId("5cba059d7219729fde21ddb3"),
"StudentName" : "Chris",
"StudentMathMarks" : 82
}
{
"_id" : ObjectId("5cba059d7219729fde21ddb4"),
"StudentName" : "John",
"StudentMathMarks" : "100"
}Following is the query to find the highest numeric value of a column −
> db.highestNumericValueOfAColumnDemo.find({StudentMathMarks: {$not: {$type:
2}}}).sort({StudentMathMarks: -1}).limit(1).pretty();This will produce the following output −
{
"_id" : ObjectId("5cba059d7219729fde21ddb3"),
"StudentName" : "Chris",
"StudentMathMarks" : 82
}The above query ignores the string value, so we are getting only the integer highest value which is 82.