The max aggregate returns the maximum value of a set of scalar values from an array attribute.

Synopsis

aggregate(array, max(attribute) [,dimension_1, dimension_2,...])

Summary

The max aggregate takes a set of scalar values from an array attribute and returns the maximum value. You can optionally specify one or more dimensions by which to group.

• The maximum value of an empty set is NULL.
• The maximum of a set that contains only NULL values is also NULL.
• If the set contains NULL and NOT NULL values, the max aggregate considers only NOT NULL values.

Example

To find the maximum value of each row of a 2-dimensional array, do the following:

1. Create a 1-attribute, 2x3-dimensional array called m2x3: 

   AFL% store(build(<val:double>[r=1:2; c=1:3],
   '[
       [3,2,1]
       [1,4,3]
   ]',true),m2x3); 

   
   The output is:

   {1,1} 3
   {1,2} 2
   {1,3} 1
   {2,1} 1
   {2,2} 4
   {2,3} 3

2. Select the maximum value of each row of m2x3:

   AFL% aggregate(m2x3,max(val),r);

   
   The output is:

   {r} val_max
   {1} 3
   {2} 4

3. Select the maximum value of each column of m2x3:

   AFL% aggregate(m2x3,max(val),c);

   The output is:

   {c} val_max
   {1} 3
   {2} 4
   {3} 3

4. Remove the example array:

   AFL% remove(m2x3);