fix: Change in condition builder

frappe/model/db_query.py

@@ -840,16 +840,20 @@ def prepare_filter_condition(self, f):
 
 			elif f.operator.lower() == "is":
 				if f.value == "set":
-					f.operator = "!="
+					f.operator = "IS NOT NULL" if frappe.conf.db_type == "postgres" else "!="
 					# Value can technically be null, but comparing with null will always be falsy
 					# Not using coalesce here is faster because indexes can be used.
 					# null != '' -> null ~ falsy
 					# '' != '' -> false
 					can_be_null = False
-				elif f.value == "not set":
-					f.operator = "="
-					fallback = "''"
-					can_be_null = True
+				elif f.value == "not set": 
+					if frappe.conf.db_type == "postgres":
+						f.operator = "IS NULL" 
+						can_be_null = False
+					else:
+						f.operator = "="
+						fallback = "''"
+						can_be_null = True
 
 				value = ""
 
@@ -897,7 +901,7 @@ def prepare_filter_condition(self, f):
 				value = f"{tname}.{quote}{f.value.name}{quote}"
 
 			# escape value
-			elif escape and isinstance(value, str):
+			elif escape and isinstance(value, str) and frappe.conf.db_type != "postgres":
 				value = f"{frappe.db.escape(value, percent=False)}"
 
 		if (