arangodb/Documentation/Books/AQL/Operations

!CHAPTER High-level operations

The following high-level operations are described here after: 

* [FOR](../AqlOperations/For.md) : to iterate over all elements of an array.
* [RETURN](../AqlOperations/Return.md) : to produce the result of a query.
* [FILTER](../AqlOperations/Filter.md) : to restrict the results to elements that match an arbitrary logical condition. 
* [SORT](../AqlOperations/Sort.md) : to force a sort of the array of already produced intermediate results. 
* [LIMIT](../AqlOperations/Limit.md) : to reduce the number of elements in the result to at most the specified number.  
* [LET](../AqlOperations/Let.md) : to assign an arbitrary value to a variable.  
* [COLLECT](../AqlOperations/Collect.md) : to group an array by one or multiple group criteria. 
* [REMOVE](../AqlOperations/Remove.md) : to remove documents from a collection. 
* [UPDATE](../AqlOperations/Update.md) : to partially update documents in a collection. 
* [REPLACE](../AqlOperations/Replace.md) :  to completely replace documents in a collection. 
* [INSERT](../AqlOperations/Insert.md) : to insert new documents into a collection. 
* [UPSERT](../AqlOperations/Upsert.md) : to update an existing document, or create it in the case it does not exist.