cursor.min()

The min() method specifies the inclusive lower bound for a specific index in order to constrain the results of find(). min() provides a way to specify lower bounds on compound key indexes.

min() takes the following parameter:

Consider the following example of min(), which assumes a collection named products that holds the following documents:

{ "_id" : 6, "item" : "apple", "type" : "cortland", "price" : 1.29 }
{ "_id" : 2, "item" : "apple", "type" : "fuji", "price" : 1.99 }
{ "_id" : 1, "item" : "apple", "type" : "honey crisp", "price" : 1.99 }
{ "_id" : 3, "item" : "apple", "type" : "jonagold", "price" : 1.29 }
{ "_id" : 4, "item" : "apple", "type" : "jonathan", "price" : 1.29 }
{ "_id" : 5, "item" : "apple", "type" : "mcintosh", "price" : 1.29 }
{ "_id" : 7, "item" : "orange", "type" : "cara cara", "price" : 2.99 }
{ "_id" : 10, "item" : "orange", "type" : "navel", "price" : 1.39 }
{ "_id" : 9, "item" : "orange", "type" : "satsuma", "price" : 1.99 }
{ "_id" : 8, "item" : "orange", "type" : "valencia", "price" : 0.99 }

The collection has the following indexes:

{ "_id" : 1 }
{ "item" : 1, "type" : 1 }
{ "item" : 1, "type" : -1 }
{ "price" : 1 }

• Using the ordering of { item: 1, type: 1 } index, min() limits the query to the documents that are at or above the index key bound of item equal to apple and type equal to jonagold, as in the following:

  db.products.find().min( { item: 'apple', type: 'jonagold' } ).hint( { item: 1, type: 1 } )
  

  The query returns the following documents:

  { "_id" : 3, "item" : "apple", "type" : "jonagold", "price" : 1.29 }
  { "_id" : 4, "item" : "apple", "type" : "jonathan", "price" : 1.29 }
  { "_id" : 5, "item" : "apple", "type" : "mcintosh", "price" : 1.29 }
  { "_id" : 7, "item" : "orange", "type" : "cara cara", "price" : 2.99 }
  { "_id" : 10, "item" : "orange", "type" : "navel", "price" : 1.39 }
  { "_id" : 9, "item" : "orange", "type" : "satsuma", "price" : 1.99 }
  { "_id" : 8, "item" : "orange", "type" : "valencia", "price" : 0.99 }
  

  If the query did not explicitly specify the index with the hint() method, it is ambiguous as to whether mongod would select the { item: 1, type: 1 } index ordering or the { item: 1, type: -1 } index ordering.

• Using the ordering of the index { price: 1 }, min() limits the query to the documents that are at or above the index key bound of price equal to 1.39 and max() limits the query to the documents that are below the index key bound of price equal to 1.99:

  db.products.find().min( { price: 1.39 } ).max( { price: 1.99 } ).hint( { price: 1 } )
  

  The query returns the following documents:

  { "_id" : 6, "item" : "apple", "type" : "cortland", "price" : 1.29 }
  { "_id" : 4, "item" : "apple", "type" : "jonathan", "price" : 1.29 }
  { "_id" : 5, "item" : "apple", "type" : "mcintosh", "price" : 1.29 }
  { "_id" : 3, "item" : "apple", "type" : "jonagold", "price" : 1.29 }
  { "_id" : 10, "item" : "orange", "type" : "navel", "price" : 1.39 }