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This operator can be used to select one element from a window of elements.

Parameter

method (String): The method that should be used for selection
- FIRST: The first element in the window
- LAST: The last element in the window
- MIN: The element with a minimal value
- MAX: The element with a maximal value
attribute (SDFAttribute): For some methods this states the attribute for which the element should be selected.

Remark: The input must contain end time stamps, else no output will ever be produced!

Example

#PARSER PQL
#ADDQUERY
window = ELEMENTWINDOW({
              size = 5,
              advance = 5          
            },
            person
          )
out = TUPLEAGGREGATE({
          method = 'MAX',
          attribute = 'id',
          name = 'MAX'        
        },
        window
      )
      
out2 = TUPLEAGGREGATE({
            method = 'MIN',
            attribute = 'id'        
              name = 'MIN',
          },
          window
        )
      
      
out3 = TUPLEAGGREGATE({
            method = 'FIRST', 
            name = 'FIRST',
                    
          },
          window
        )
      
      
out4 = TUPLEAGGREGATE({
            method = 'LAST',
            name = 'LAST'
                    
          },
          window
        )