Feat(hive)!: parse ASCII into Unicode to facilitate transpilation

Author: georgesittas

sqlglot/dialects/hive.py

@@ -277,6 +277,7 @@ class Parser(parser.Parser):
 
         FUNCTIONS = {
             **parser.Parser.FUNCTIONS,
+            "ASCII": exp.Unicode.from_arg_list,
             "BASE64": exp.ToBase64.from_arg_list,
             "COLLECT_LIST": lambda args: exp.ArrayAgg(this=seq_get(args, 0), nulls_excluded=True),
             "COLLECT_SET": exp.ArrayUniqueAgg.from_arg_list,
@@ -582,6 +583,7 @@ class Generator(generator.Generator):
             exp.TsOrDsDiff: _date_diff_sql,
             exp.TsOrDsToDate: _to_date_sql,
             exp.TryCast: no_trycast_sql,
+            exp.Unicode: rename_func("ASCII"),
             exp.UnixToStr: lambda self, e: self.func(
                 "FROM_UNIXTIME", e.this, time_format("hive")(self, e)
             ),

tests/dialects/test_sqlite.py

@@ -95,9 +95,12 @@ def test_sqlite(self):
         self.validate_all(
             "UNICODE(x)",
             write={
+                "": "UNICODE(x)",
                 "mysql": "ORD(CONVERT(x USING utf32))",
-                "postgres": "ASCII(x)",
                 "oracle": "ASCII(UNISTR(x))",
+                "postgres": "ASCII(x)",
+                "redshift": "ASCII(x)",
+                "spark": "ASCII(x)",
             },
         )
         self.validate_identity(