Repository: tobymao/sqlglot

Issue:
Support for Databricks UNPIVOT Options
Databricks dialect does not support the Option INCLUDE NULLS/EXCLUDE NULLS: https://docs.databricks.com/en/sql/language-manual/sql-ref-syntax-qry-select-unpivot.html

sample sql:
```sql
select id
    , level
    , conditions
  FROM bla.table_name UNPIVOT INCLUDE NULLS
  (conditions FOR level IN (KONTR1
                            ,KONTR2
                            ,KONTR3
                            ,KONTR4))
```




Discussion:

Resolving patch:
diff --git a/sqlglot/expressions.py b/sqlglot/expressions.py
--- a/sqlglot/expressions.py
+++ b/sqlglot/expressions.py
@@ -3309,6 +3309,7 @@ class Pivot(Expression):
         "using": False,
         "group": False,
         "columns": False,
+        "include_nulls": False,
     }
 
 
diff --git a/sqlglot/generator.py b/sqlglot/generator.py
--- a/sqlglot/generator.py
+++ b/sqlglot/generator.py
@@ -1290,7 +1290,12 @@ def pivot_sql(self, expression: exp.Pivot) -> str:
         unpivot = expression.args.get("unpivot")
         direction = "UNPIVOT" if unpivot else "PIVOT"
         field = self.sql(expression, "field")
-        return f"{direction}({expressions} FOR {field}){alias}"
+        include_nulls = expression.args.get("include_nulls")
+        if include_nulls is not None:
+            nulls = " INCLUDE NULLS " if include_nulls else " EXCLUDE NULLS "
+        else:
+            nulls = ""
+        return f"{direction}{nulls}({expressions} FOR {field}){alias}"
 
     def tuple_sql(self, expression: exp.Tuple) -> str:
         return f"({self.expressions(expression, flat=True)})"
diff --git a/sqlglot/parser.py b/sqlglot/parser.py
--- a/sqlglot/parser.py
+++ b/sqlglot/parser.py
@@ -2623,11 +2623,18 @@ def _parse_on() -> t.Optional[exp.Expression]:
 
     def _parse_pivot(self) -> t.Optional[exp.Pivot]:
         index = self._index
+        include_nulls = None
 
         if self._match(TokenType.PIVOT):
             unpivot = False
         elif self._match(TokenType.UNPIVOT):
             unpivot = True
+
+            # https://docs.databricks.com/en/sql/language-manual/sql-ref-syntax-qry-select-unpivot.html#syntax
+            if self._match_text_seq("INCLUDE", "NULLS"):
+                include_nulls = True
+            elif self._match_text_seq("EXCLUDE", "NULLS"):
+                include_nulls = False
         else:
             return None
 
@@ -2658,7 +2665,13 @@ def _parse_pivot(self) -> t.Optional[exp.Pivot]:
 
         self._match_r_paren()
 
-        pivot = self.expression(exp.Pivot, expressions=expressions, field=field, unpivot=unpivot)
+        pivot = self.expression(
+            exp.Pivot,
+            expressions=expressions,
+            field=field,
+            unpivot=unpivot,
+            include_nulls=include_nulls,
+        )
 
         if not self._match_set((TokenType.PIVOT, TokenType.UNPIVOT), advance=False):
             pivot.set("alias", self._parse_table_alias())


Test patch:
diff --git a/tests/dialects/test_databricks.py b/tests/dialects/test_databricks.py
--- a/tests/dialects/test_databricks.py
+++ b/tests/dialects/test_databricks.py
@@ -11,6 +11,12 @@ def test_databricks(self):
         self.validate_identity("CREATE FUNCTION a AS b")
         self.validate_identity("SELECT ${x} FROM ${y} WHERE ${z} > 1")
         self.validate_identity("CREATE TABLE foo (x DATE GENERATED ALWAYS AS (CAST(y AS DATE)))")
+        self.validate_identity(
+            "SELECT * FROM sales UNPIVOT INCLUDE NULLS (sales FOR quarter IN (q1 AS `Jan-Mar`))"
+        )
+        self.validate_identity(
+            "SELECT * FROM sales UNPIVOT EXCLUDE NULLS (sales FOR quarter IN (q1 AS `Jan-Mar`))"
+        )
 
         self.validate_all(
             "CREATE TABLE foo (x INT GENERATED ALWAYS AS (YEAR(y)))",