Similar to Java in PHP only set Select PARAMETER with value 'COUNT'
$result = $aws->query(array(
'TableName' => 'game_table',
'IndexName' => 'week-point-index',
'KeyConditions' => array(
'week' => array(
'ComparisonOperator' => 'EQ',
'AttributeValueList' => array(
array(Type::STRING => $week)
)
),
'point' => array(
'ComparisonOperator' => 'GE',
'AttributeValueList' => array(
array(Type::NUMBER => $my_point)
)
)
),
'Select' => 'COUNT'
));
and acces it just like this :
echo $result['Count'];
but as Saumitra mentioned above be careful with resultsets largers than 1 MB, in that case use LastEvaluatedKey til it returns null to get the last updated count value.