CARDINALITY function

The CARDINALITY function returns the number of elements in a list.

Syntax

CARDINALITY returns an integer value giving the number of elements in the list specified by ListExpression.

ListExpression is any expression that returns a list. All the following, for example, return a list:

A LIST constructor
A field reference with the [] array indicator
Some SELECT expressions (not all return a list)

A common use of this function is to determine the number of fields in a list before iterating over them.

Examples

-- Determine the number of F1 fields in the message.
-- Note that the [ ] are required   
DECLARE CountF1 INT CARDINALITY(OutputRoot.XMLNS.Data.Source.F1[]);

-- Determine the number of fields called F1 with the value 'F12' in the message.
-- Again note that the [ ] are required
DECLARE CountF1F12 INT     
  CARDINALITY(SELECT F.* FROM OutputRoot.XMLNS.Data.Source.F1[] AS F 
              where F = 'F12');

-- Use the value returned by CARDINALITY to refer to a specific element 
-- in a list or array:
-- Array indices start at 1, so this example refers to the third-from-last
-- instance of the Item field
Body.Invoice.Item[CARDINALITY(Body.Invoice.Item[]) - 2].Quantity