1 files changed, 87 insertions, 0 deletions
diff --git a/sqlglot/dialects/teradata.py b/sqlglot/dialects/teradata.py
new file mode 100644
index 0000000..4340820
--- /dev/null
+++ b/sqlglot/dialects/teradata.py
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+from __future__ import annotations
+
+from sqlglot import exp, generator, parser
+from sqlglot.dialects.dialect import Dialect
+from sqlglot.tokens import TokenType
+
+
+class Teradata(Dialect):
+    class Parser(parser.Parser):
+        CHARSET_TRANSLATORS = {
+            "GRAPHIC_TO_KANJISJIS",
+            "GRAPHIC_TO_LATIN",
+            "GRAPHIC_TO_UNICODE",
+            "GRAPHIC_TO_UNICODE_PadSpace",
+            "KANJI1_KanjiEBCDIC_TO_UNICODE",
+            "KANJI1_KanjiEUC_TO_UNICODE",
+            "KANJI1_KANJISJIS_TO_UNICODE",
+            "KANJI1_SBC_TO_UNICODE",
+            "KANJISJIS_TO_GRAPHIC",
+            "KANJISJIS_TO_LATIN",
+            "KANJISJIS_TO_UNICODE",
+            "LATIN_TO_GRAPHIC",
+            "LATIN_TO_KANJISJIS",
+            "LATIN_TO_UNICODE",
+            "LOCALE_TO_UNICODE",
+            "UNICODE_TO_GRAPHIC",
+            "UNICODE_TO_GRAPHIC_PadGraphic",
+            "UNICODE_TO_GRAPHIC_VarGraphic",
+            "UNICODE_TO_KANJI1_KanjiEBCDIC",
+            "UNICODE_TO_KANJI1_KanjiEUC",
+            "UNICODE_TO_KANJI1_KANJISJIS",
+            "UNICODE_TO_KANJI1_SBC",
+            "UNICODE_TO_KANJISJIS",
+            "UNICODE_TO_LATIN",
+            "UNICODE_TO_LOCALE",
+            "UNICODE_TO_UNICODE_FoldSpace",
+            "UNICODE_TO_UNICODE_Fullwidth",
+            "UNICODE_TO_UNICODE_Halfwidth",
+            "UNICODE_TO_UNICODE_NFC",
+            "UNICODE_TO_UNICODE_NFD",
+            "UNICODE_TO_UNICODE_NFKC",
+            "UNICODE_TO_UNICODE_NFKD",
+        }
+
+        FUNCTION_PARSERS = {
+            **parser.Parser.FUNCTION_PARSERS,  # type: ignore
+            "TRANSLATE": lambda self: self._parse_translate(self.STRICT_CAST),
+        }
+
+        def _parse_translate(self, strict: bool) -> exp.Expression:
+            this = self._parse_conjunction()
+
+            if not self._match(TokenType.USING):
+                self.raise_error("Expected USING in TRANSLATE")
+
+            if self._match_texts(self.CHARSET_TRANSLATORS):
+                charset_split = self._prev.text.split("_TO_")
+                to = self.expression(exp.CharacterSet, this=charset_split[1])
+            else:
+                self.raise_error("Expected a character set translator after USING in TRANSLATE")
+
+            return self.expression(exp.Cast if strict else exp.TryCast, this=this, to=to)
+
+        # FROM before SET in Teradata UPDATE syntax
+        # https://docs.teradata.com/r/Enterprise_IntelliFlex_VMware/Teradata-VantageTM-SQL-Data-Manipulation-Language-17.20/Statement-Syntax/UPDATE/UPDATE-Syntax-Basic-Form-FROM-Clause
+        def _parse_update(self) -> exp.Expression:
+            return self.expression(
+                exp.Update,
+                **{  # type: ignore
+                    "this": self._parse_table(alias_tokens=self.UPDATE_ALIAS_TOKENS),
+                    "from": self._parse_from(),
+                    "expressions": self._match(TokenType.SET)
+                    and self._parse_csv(self._parse_equality),
+                    "where": self._parse_where(),
+                },
+            )
+
+    class Generator(generator.Generator):
+        # FROM before SET in Teradata UPDATE syntax
+        # https://docs.teradata.com/r/Enterprise_IntelliFlex_VMware/Teradata-VantageTM-SQL-Data-Manipulation-Language-17.20/Statement-Syntax/UPDATE/UPDATE-Syntax-Basic-Form-FROM-Clause
+        def update_sql(self, expression: exp.Update) -> str:
+            this = self.sql(expression, "this")
+            from_sql = self.sql(expression, "from")
+            set_sql = self.expressions(expression, flat=True)
+            where_sql = self.sql(expression, "where")
+            sql = f"UPDATE {this}{from_sql} SET {set_sql}{where_sql}"
+            return self.prepend_ctes(expression, sql)