From 51cfc8181e55fa09934363120e208fe9bbc14877 Mon Sep 17 00:00:00 2001
From: Kaushal Shriwas <64089478+kaulith@users.noreply.github.com>
Date: Wed, 8 Apr 2026 10:57:07 +0530
Subject: [PATCH] perf(query): replace Coalesce with OR IS NULL in func_in
 (#38336)

---
 frappe/database/operator_map.py    |  3 +--
 frappe/tests/test_query_builder.py | 11 +++++++----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/frappe/database/operator_map.py b/frappe/database/operator_map.py
index c8cb9aa099..218983a318 100644
--- a/frappe/database/operator_map.py
+++ b/frappe/database/operator_map.py
@@ -8,7 +8,6 @@ import frappe
 from frappe.database.utils import NestedSetHierarchy
 from frappe.model.db_query import get_timespan_date_range
 from frappe.query_builder import Field
-from frappe.query_builder.functions import Coalesce
 from frappe.utils import cstr
 
 
@@ -51,7 +50,7 @@ def func_in(key: Field, value: list | tuple) -> frappe.qb:
 
 	value = ["" if v is None else v for v in value]
 	if "" in value:
-		return Coalesce(key, "").isin(value)
+		return key.isin(value) | key.isnull()
 	return key.isin(value)
 
 
diff --git a/frappe/tests/test_query_builder.py b/frappe/tests/test_query_builder.py
index 920b06e4af..f0df927238 100644
--- a/frappe/tests/test_query_builder.py
+++ b/frappe/tests/test_query_builder.py
@@ -525,15 +525,17 @@ class TestOperatorIn(IntegrationTestCase):
 		query = func_in(note.name, [None, "user1"])
 		sql_str = str(query).lower()
 
-		self.assertIn("coalesce", sql_str)
+		self.assertNotIn("coalesce", sql_str)
+		self.assertIn("is null", sql_str)
 		self.assertIn("''", sql_str)
 
-	def test_func_in_with_empty_string_uses_coalesce(self):
+	def test_func_in_with_empty_string_uses_or_is_null(self):
 		note = frappe.qb.DocType("Note")
 		query = func_in(note.name, ["", "user1"])
 		sql_str = str(query).lower()
 
-		self.assertIn("coalesce", sql_str)
+		self.assertNotIn("coalesce", sql_str)
+		self.assertIn("is null", sql_str)
 		self.assertIn("''", sql_str)
 
 	def test_func_in_with_mixed_none_and_values(self):
@@ -541,7 +543,8 @@ class TestOperatorIn(IntegrationTestCase):
 		query = func_in(note.name, ["val1", None, "val2"])
 		sql_str = str(query).lower()
 
-		self.assertIn("coalesce", sql_str)
+		self.assertNotIn("coalesce", sql_str)
+		self.assertIn("is null", sql_str)
 
 	def test_in_filter_matches_null_and_empty_columns(self):
 		test_doctype = new_doctype(