diff --git a/erpnext/stock/doctype/item_attribute/item_attribute.py b/erpnext/stock/doctype/item_attribute/item_attribute.py
index 2e50479b409..822d257e050 100644
--- a/erpnext/stock/doctype/item_attribute/item_attribute.py
+++ b/erpnext/stock/doctype/item_attribute/item_attribute.py
@@ -66,18 +66,15 @@ class ItemAttribute(Document):
 		attributes_list = [d.attribute_value for d in self.item_attribute_values]
 
 		# Get Item Variant Attribute details of variant items
-		items = frappe.db.sql(
-			"""
-			select
-				i.name, iva.attribute_value as value
-			from
-				`tabItem Variant Attribute` iva, `tabItem` i
-			where
-				iva.attribute = %(attribute)s
-				and iva.parent = i.name and
-				i.variant_of is not null and i.variant_of != ''""",
-			{"attribute": self.name},
-			as_dict=1,
+		iva = frappe.qb.DocType("Item Variant Attribute")
+		i = frappe.qb.DocType("Item")
+		items = (
+			frappe.qb.from_(iva)
+			.inner_join(i)
+			.on(iva.parent == i.name)
+			.select(i.name, iva.attribute_value.as_("value"))
+			.where((iva.attribute == self.name) & i.variant_of.isnotnull() & (i.variant_of != ""))
+			.run(as_dict=1)
 		)
 
 		for item in items:
diff --git a/erpnext/stock/doctype/item_attribute/test_item_attribute.py b/erpnext/stock/doctype/item_attribute/test_item_attribute.py
index 63958733eba..2d45e94a4fc 100644
--- a/erpnext/stock/doctype/item_attribute/test_item_attribute.py
+++ b/erpnext/stock/doctype/item_attribute/test_item_attribute.py
@@ -30,3 +30,22 @@ class TestItemAttribute(ERPNextTestSuite):
 
 		item_attribute.increment = 0.5
 		item_attribute.save()
+
+	def test_validate_existing_items_finds_variants(self):
+		# validate_exising_items() joins Item Variant Attribute to Item to find variants using this
+		# attribute. Exercises the converted query builder version on both engines and asserts it
+		# finds the variant (the raise only fires if the query returned the variant row).
+		from erpnext.controllers.item_variant import InvalidItemAttributeValueError, create_variant
+
+		frappe.delete_doc_if_exists("Item", "_Test Variant Item-L", force=1)
+		variant = create_variant("_Test Variant Item", {"Test Size": "Large"})
+		variant.save()
+		self.addCleanup(frappe.delete_doc_if_exists, "Item", "_Test Variant Item-L", force=1)
+
+		attribute = frappe.get_doc("Item Attribute", "Test Size")
+		attribute.item_attribute_values = []
+		frappe.flags.attribute_values = None
+
+		# "Large" is no longer a permitted value, so the variant found by validate_exising_items
+		# is invalid; the save must abort (and so never persists the cleared values).
+		self.assertRaises(InvalidItemAttributeValueError, attribute.save)