fix: handle distinct for fieldname (#25511) (#25515)

`distinct count(fieldname)` is supported well but `count(distinct fieldname)` fails if fieldname contains full field with table name included. This PR just adds basic handling for it.

Needs to be rewritten entirely in QB __some day__.

(cherry picked from commit 8a7beeb)

# Conflicts:
#	frappe/model/db_query.py

Co-authored-by: Ankush Menat <ankush@frappe.io>

frappe/model/db_query.py

@@ -472,7 +472,9 @@ def extract_tables(self):
 
 				if table_name.lower().startswith("group_concat("):
 					table_name = table_name[13:]
-				if not table_name[0] == "`":
+				if table_name.lower().startswith("distinct"):
+					table_name = table_name[8:].strip()
+				if table_name[0] != "`":
 					table_name = f"`{table_name}`"
 				if (
 					table_name not in self.query_tables

frappe/public/js/frappe/list/list_view.js

@@ -987,7 +987,7 @@ frappe.views.ListView = class ListView extends frappe.views.BaseList {
 				if (this.count_without_children) {
 					str = __("{0} of {1} ({2} rows with children)", [
 						count_without_children,
-						this.total_count,
+						count_str,
 						current_count,
 					]);
 				}

frappe/tests/test_db_query.py

@@ -14,6 +14,7 @@
 from frappe.model.db_query import DatabaseQuery, get_between_date_filter
 from frappe.permissions import add_user_permission, clear_user_permissions_for_doctype
 from frappe.query_builder import Column
+from frappe.tests.test_query_builder import db_type_is, run_only_if
 from frappe.tests.utils import FrappeTestCase
 from frappe.utils.testutils import add_custom_field, clear_custom_fields
 
@@ -1182,6 +1183,7 @@ def test_ambiguous_linked_tables(self):
 
 
 class TestReportView(FrappeTestCase):
+	@run_only_if(db_type_is.MARIADB)  # TODO: postgres name casting is messed up
 	def test_get_count(self):
 		frappe.local.request = frappe._dict()
 		frappe.local.request.method = "GET"
@@ -1241,6 +1243,20 @@ def test_get_count(self):
 		self.assertIsInstance(count, int)
 		self.assertLessEqual(count, limit)
 
+		# test with distinct
+		limit = 2
+		frappe.local.form_dict = frappe._dict(
+			{
+				"doctype": "DocType",
+				"fields": [],
+				"distinct": "true",
+				"limit": limit,
+			}
+		)
+		count = execute_cmd("frappe.desk.reportview.get_count")
+		self.assertIsInstance(count, int)
+		self.assertLessEqual(count, limit)
+
 	def test_reportview_get(self):
 		user = frappe.get_doc("User", "test@example.com")
 		add_child_table_to_blog_post()