Seitenvergleich

// Search all cities in the U.S. State of California. (CA)
// all the following queries return the same result
 
// standard MongoDB query
{state: "CA"}
 
// If there is no options object, the curly braces can be omitted
state: "CA"
 
// You can also write everything in quotation marks
"state": "CA"
 
// Or use single quotes
state: 'CA'

MongoDB queries always distinguishes between upper and lowercase. To work around this, you can use Regular Expressions.

//Find all cities in the U.S. State of Alabama(AL) with more than 40,000 inhabitants
 
// standard MongoDB query
{
	state: "AL",
	pop: {
		$gt: 40000
	}
}
 
// shortened query
state: "AL", pop: {$gt: 40000}
 
// shortened query without whitespaces
state:"AL",pop:{$gt:40000}

// Find all cities in the U.S. State of Alabama(AL) with more than 40,000 inhabitants and return only the names of the cities as result
{state: "AL", pop: {$gt: 40000}}, {fields: {city: 1}}

// Array Syntax
{state: "AL", pop: {$gt: 40000}}, {fields: ['city']}

// also id field leave out
{state: "AL", pop: {$gt: 40000}}, {fields: {city: 1, _id: 0}}
 
// Find all cities in the U.S. State of Alabama(AL) with a population of more than 10,000 and sort in ascending order by city name
{state: "AL", pop: {$gt: 10000}}, {sort: {city: 1}}
 
// Find all cities in the U.S. State of Alabama(AL) with a population of more than 10,000 and return 10 documents, whereby the first 20 documents are skipped
{state: "AL", pop: {$gt: 10000}}, {limit: 10, skip: 20}

Mongo Management Studio erkennt Strings, die das Format einer MongoDB ObjectId haben und konvertiert dieses dann. Sollte es passieren, dass in einer Collection _ids als Strings gespeichert und diese MongoDB ObjectId konform sind, muss man für die Suchabfrage über den Konsolenmodus verwenden. Ansonsten werden keine Daten gefunden.

recognizes strings,having the format of a MongoDB ObjectId and converts them. Should it happen that _ids stored as strings in a collection and they are compliant to MongoDB ObjectId, you have to use the Console mode for the query. Otherwise, no data is found.

// findefind Personpersons mitwith id '52bd27ebf370afe931001364'
db.persons.find{_id: '52bd27ebf370afe931001364'}

 works in milliseconds, UNIX timestamps must be multiplied by 1000 to be correctly converted or displayed.

Es muss der komplette Regex-Ausdruck angegeben werden, um den entsprechenen Datensatz mit dem richtigen Wert zu erhaltenYou must specify the complete regex expression to obtain the corresponding document with the correct value.

In der derzeitigen Version werden lediglich die Parameter the current version only the parameter "i" sowie and "m" als Optionen bei der Kurzschreibweise unterstützt. Die Parameter are supported as options in the short notation. The parameter "s" und and "x" folgen in einer späteren Versionfollow in a later version.

Genauere Informationen zum Gebrauch von Regex-Ausdrücken in Abfragen kann man hier nachlesen Here you can read more detailed information about the use of regex expressions in queries: http://docs.mongodb.org/manual/reference/operator/query/regex/