perf: avoid coalescing wherever possible (#17920) (#17925)

(cherry picked from commit cdb0732646)

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

frappe/model/db_query.py

@@ -612,6 +612,9 @@ class DatabaseQuery:
 			)
 
 		elif f.operator.lower() in ("in", "not in"):
+			# if values contain '' or falsy values then only coalesce column
+			can_be_null = not f.value or any(v is None or v == "" for v in f.value)
+
 			values = f.value or ""
 			if isinstance(values, str):
 				values = values.split(",")

frappe/tests/test_db_query.py

@@ -745,6 +745,11 @@ class TestReportview(unittest.TestCase):
 
 		self.assertTrue(dashboard_settings)
 
+	def test_coalesce_with_in_ops(self):
+		self.assertNotIn("ifnull", frappe.get_all("User", {"name": ("in", ["a", "b"])}, run=0))
+		self.assertIn("ifnull", frappe.get_all("User", {"name": ("in", ["a", None])}, run=0))
+		self.assertIn("ifnull", frappe.get_all("User", {"name": ("in", ["a", ""])}, run=0))
+
 
 def add_child_table_to_blog_post():
 	child_table = frappe.get_doc(