fix(duckdb): Make exp.DateFromParts more lenient (#6397)

Author: VaggelisD

sqlglot/expressions.py

@@ -6493,7 +6493,7 @@ class TimeTrunc(Func, TimeUnit):
 
 class DateFromParts(Func):
     _sql_names = ["DATE_FROM_PARTS", "DATEFROMPARTS"]
-    arg_types = {"year": True, "month": True, "day": True}
+    arg_types = {"year": True, "month": False, "day": False}
 
 
 class TimeFromParts(Func):

tests/dialects/test_duckdb.py

@@ -1240,6 +1240,9 @@ def test_duckdb(self):
         )
         self.validate_identity("SELECT GREATEST(1.0, 2.5, NULL, 3.7)")
 
+        # TODO: This is incorrect AST, DATE_PART creates a STRUCT of values but it's stored in 'year' arg
+        self.validate_identity("SELECT MAKE_DATE(DATE_PART(['year', 'month', 'day'], TODAY()))")
+
     def test_array_index(self):
         with self.assertLogs(helper_logger) as cm:
             self.validate_all(