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Head (MDX)

  • Άρθρο

Returns the first specified number of elements in a set, while retaining duplicates.

Syntax

  
Head(Set_Expression [ ,Count ] )

Arguments

Set_Expression
A valid Multidimensional Expressions (MDX) expression that returns a set.

Count
A valid numeric expression that specifies the number of tuples to be returned.

Remarks

The Head function returns the specified number of tuples from the beginning of the specified set. The order of elements is preserved. The default value of Count is 1. If the specified number of tuples is less than 1, the Head function returns an empty set. If the specified number of tuples exceeds the number of tuples in the set, the function returns the original set.

Example

The following example returns top five selling subcategories of products, irrespective of hierarchy, based on Reseller Gross Profit. The Head function is used to return only the first 5 sets in the result after the result is ordered using the Order function.

SELECT   
[Measures].[Reseller Gross Profit] ON 0,  
Head  
   (Order   
      ([Product].[Product Categories].[SubCategory].members  
         ,[Measures].[Reseller Gross Profit]  
         ,BDESC  
      )  
   ,5  
   ) ON 1  
FROM [Adventure Works]

See Also

Tail (MDX)
Item (Tuple) (MDX)
Item (Member) (MDX)
Rank (MDX)
MDX Function Reference (MDX)