#434

backend/app/services/counts_axes.rb

@@ -40,7 +40,7 @@ class CountsAxes
   end
 
   def expressions
-    all.map do |axis|
+    @expressions ||= all.map do |axis|
       field = axis.fetch('field')
       case field
       when 'tags'
@@ -56,9 +56,9 @@ class CountsAxes
     end
   end
 
-  def joins
+  def joins(fields = all.map { _1['field'] })
     result = ''
-    if all.any? { _1['field'] == 'tags' }
+    if fields.include?('tags')
       result += <<~SQL.squish
          JOIN JSON_TABLE(CAST(v.tags_json AS JSON), '$[*]' COLUMNS (
           tag_id BIGINT PATH '$.tag_id' NULL ON EMPTY,
@@ -66,7 +66,7 @@ class CountsAxes
 
       SQL
     end
-    if all.any? { _1['field'] == 'changed_field' }
+    if fields.include?('changed_field')
       fields = @definition.changes.map do |field|
         "SELECT #{ ApplicationRecord.connection.quote(field) } AS field_key"
       end.join(' UNION ALL ')
@@ -89,6 +89,8 @@ class CountsAxes
       raise ArgumentError unless @definition.axes(@population.history).include?(axis['field'])
       if @definition.fields[axis['field']] == :datetime
         raise ArgumentError unless GRAINS.include?(axis.fetch('grain', 'month'))
+
+        axis['grain'] ||= 'month'
       elsif axis.key?('grain')
         raise ArgumentError
       end