fix: > 1 nested joins closes #3231

sqlglot/generator.py

@@ -1636,7 +1636,9 @@ def table_sql(self, expression: exp.Table, sep: str = " AS ") -> str:
         hints = f" {hints}" if hints and self.TABLE_HINTS else ""
         pivots = self.expressions(expression, key="pivots", sep=" ", flat=True)
         pivots = f" {pivots}" if pivots else ""
-        joins = self.expressions(expression, key="joins", sep="", skip_first=True)
+        joins = self.indent(
+            self.expressions(expression, key="joins", sep="", flat=True), skip_first=True
+        )
         laterals = self.expressions(expression, key="laterals", sep="")
 
         file_format = self.sql(expression, "format")

sqlglot/parser.py

@@ -2658,7 +2658,7 @@ def _parse_query_modifiers(
         self, this: t.Optional[exp.Expression]
     ) -> t.Optional[exp.Expression]:
         if isinstance(this, (exp.Query, exp.Table)):
-            for join in iter(self._parse_join, None):
+            for join in self._parse_joins():
                 this.append("joins", join)
             for lateral in iter(self._parse_lateral, None):
                 this.append("laterals", lateral)
@@ -2903,19 +2903,21 @@ def _parse_join(
             kwargs["on"] = self._parse_conjunction()
         elif self._match(TokenType.USING):
             kwargs["using"] = self._parse_wrapped_id_vars()
-        elif not (kind and kind.token_type == TokenType.CROSS):
+        elif not isinstance(kwargs["this"], exp.Unnest) and not (
+            kind and kind.token_type == TokenType.CROSS
+        ):
             index = self._index
-            join = self._parse_join()
+            joins: t.Optional[list] = list(self._parse_joins())
 
-            if join and self._match(TokenType.ON):
+            if joins and self._match(TokenType.ON):
                 kwargs["on"] = self._parse_conjunction()
-            elif join and self._match(TokenType.USING):
+            elif joins and self._match(TokenType.USING):
                 kwargs["using"] = self._parse_wrapped_id_vars()
             else:
-                join = None
+                joins = None
                 self._retreat(index)
 
-            kwargs["this"].set("joins", [join] if join else None)
+            kwargs["this"].set("joins", joins if joins else None)
 
         comments = [c for token in (method, side, kind) if token for c in token.comments]
         return self.expression(exp.Join, comments=comments, **kwargs)
@@ -3152,7 +3154,7 @@ def _parse_table(
             this = table_sample
 
         if joins:
-            for join in iter(self._parse_join, None):
+            for join in self._parse_joins():
                 this.append("joins", join)
 
         if self._match_pair(TokenType.WITH, TokenType.ORDINALITY):
@@ -3301,6 +3303,9 @@ def _parse_table_sample(self, as_modifier: bool = False) -> t.Optional[exp.Table
     def _parse_pivots(self) -> t.Optional[t.List[exp.Pivot]]:
         return list(iter(self._parse_pivot, None)) or None
 
+    def _parse_joins(self) -> t.Iterator[exp.Join]:
+        return iter(self._parse_join, None)
+
     # https://duckdb.org/docs/sql/statements/pivot
     def _parse_simplified_pivot(self) -> exp.Pivot:
         def _parse_on() -> t.Optional[exp.Expression]:

tests/fixtures/pretty.sql

@@ -384,3 +384,14 @@ JOIN b
 CROSS JOIN d
 JOIN e
   ON d.id = e.id;
+
+SELECT * FROM a JOIN b JOIN c USING (e) JOIN d USING (f) USING (g);
+SELECT
+  *
+FROM a
+JOIN b
+  JOIN c
+    USING (e)
+  JOIN d
+    USING (f)
+  USING (g);

tests/test_transpile.py

@@ -518,9 +518,9 @@ def test_comments(self):
   *
 FROM x
 INNER JOIN y
+  /* inner join z */
   LEFT JOIN z
     USING (id)
-  /* inner join z */
   USING (id)""",
             pretty=True,
         )