Include selects in group query with having clause

When a grouped calculation contains a having clause that references a
selected value, we need to include that selected value in the query.

Postgres doesn't support referencing a selected value in a having
clause, but other databases do; we can skip the test on the pg adapter
but run it for the others.

This was fixed before in 9a298a1, but the test coverage was lost in
5a05207. The fix regressed in 6311975 and was removed in 97d46c1.

(cherry picked from commit 1812568)

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Fix regression of #1969 with SELECT aliases in HAVING clause.
+
+    *Eugene Kenny*
+
 *   Fix `wait_timeout` to configurable for mysql2 adapter.
 
     Fixes #26556.

activerecord/lib/active_record/relation/calculations.rb

@@ -282,7 +282,7 @@ def execute_grouped_calculation(operation, column_name, distinct) #:nodoc:
           operation,
           distinct).as(aggregate_alias)
       ]
-      select_values += select_values unless having_clause.empty?
+      select_values += self.select_values unless having_clause.empty?
 
       select_values.concat group_columns.map { |aliaz, field|
         if field.respond_to?(:as)

activerecord/test/cases/calculations_test.rb

@@ -235,7 +235,8 @@ def test_should_group_by_summed_field_having_condition
   end
 
   def test_should_group_by_summed_field_having_condition_from_select
-    c = Account.select("MIN(credit_limit) AS min_credit_limit").group(:firm_id).having("MIN(credit_limit) > 50").sum(:credit_limit)
+    skip if current_adapter?(:PostgreSQLAdapter)
+    c = Account.select("MIN(credit_limit) AS min_credit_limit").group(:firm_id).having("min_credit_limit > 50").sum(:credit_limit)
     assert_nil       c[1]
     assert_equal 60, c[2]
     assert_equal 53, c[9]