Spark3 join types (#1942)

* Add Spark3 join types

* black format and linting

* replace get_eventual_alias with method from ansi

src/sqlfluff/dialects/dialect_spark3.py

@@ -15,8 +15,11 @@
     AnyNumberOf,
     BaseSegment,
     Bracketed,
-    Delimited,
     CommentSegment,
+    Conditional,
+    Dedent,
+    Delimited,
+    Indent,
     NamedParser,
     OneOf,
     OptionallyBracketed,
@@ -693,3 +696,78 @@ class StatementSegment(BaseSegment):
             Ref("DropModelStatementSegment"),
         ],
     )
+
+
+@spark3_dialect.segment(replace=True)
+class JoinClauseSegment(BaseSegment):
+    """Any number of join clauses, including the `JOIN` keyword.
+
+    https://spark.apache.org/docs/3.0.0/sql-ref-syntax-qry-select-join.html
+    TODO: Add NATURAL JOIN syntax.
+    """
+
+    type = "join_clause"
+    match_grammar = Sequence(
+        # NB These qualifiers are optional
+        # TODO: Allow nested joins like:
+        # ....FROM S1.T1 t1 LEFT JOIN ( S2.T2 t2 JOIN S3.T3 t3 ON t2.col1=t3.col1) ON tab1.col1 = tab2.col1
+        OneOf(
+            "CROSS",
+            "INNER",
+            Sequence(
+                OneOf(
+                    "FULL",
+                    "LEFT",
+                    "RIGHT",
+                ),
+                Ref.keyword("OUTER", optional=True),
+            ),
+            Sequence(
+                Ref.keyword("LEFT", optional=True),
+                "SEMI",
+            ),
+            Sequence(
+                Ref.keyword("LEFT", optional=True),
+                "ANTI",
+            ),
+            optional=True,
+        ),
+        Ref("JoinKeywords"),
+        Indent,
+        Sequence(
+            Ref("FromExpressionElementSegment"),
+            Conditional(Dedent, indented_using_on=False),
+            # NB: this is optional
+            OneOf(
+                # ON clause
+                Ref("JoinOnConditionSegment"),
+                # USING clause
+                Sequence(
+                    "USING",
+                    Indent,
+                    Bracketed(
+                        # NB: We don't use BracketedColumnReferenceListGrammar
+                        # here because we're just using SingleIdentifierGrammar,
+                        # rather than ObjectReferenceSegment or ColumnReferenceSegment.
+                        # This is a) so that we don't lint it as a reference and
+                        # b) because the column will probably be returned anyway
+                        # during parsing.
+                        Delimited(
+                            Ref("SingleIdentifierGrammar"),
+                            ephemeral_name="UsingClauseContents",
+                        )
+                    ),
+                    Dedent,
+                ),
+                # Unqualified joins *are* allowed. They just might not
+                # be a good idea.
+                optional=True,
+            ),
+            Conditional(Indent, indented_using_on=False),
+        ),
+        Dedent,
+    )
+
+    get_eventual_alias = ansi_dialect.get_segment(
+        "JoinClauseSegment"
+    ).get_eventual_alias

test/fixtures/dialects/spark3/join_types.sql

@@ -0,0 +1,4 @@
+SELECT * FROM employee SEMI JOIN department ON employee.deptno = department.deptno;
+SELECT * FROM employee ANTI JOIN department ON employee.deptno = department.deptno;
+SELECT * FROM employee LEFT SEMI JOIN department ON employee.deptno = department.deptno;
+SELECT * FROM employee LEFT ANTI JOIN department ON employee.deptno = department.deptno;

test/fixtures/dialects/spark3/join_types.yml

@@ -0,0 +1,151 @@
+# YML test files are auto-generated from SQL files and should not be edited by
+# hand. To help enforce this, the "hash" field in the file must match a hash
+# computed by SQLFluff when running the tests. Please run
+# `python test/generate_parse_fixture_yml.py`  to generate them after adding or
+# altering SQL files.
+_hash: 083b7cabc2d0da7873019cf780c8a8e0046fd187223d5da951159dbaf4d03ca4
+file:
+- base:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          wildcard_expression:
+            wildcard_identifier:
+              star: '*'
+      from_clause:
+        keyword: FROM
+        from_expression:
+          from_expression_element:
+            table_expression:
+              table_reference:
+                identifier: employee
+            alias_expression:
+              identifier: SEMI
+          join_clause:
+            keyword: JOIN
+            from_expression_element:
+              table_expression:
+                table_reference:
+                  identifier: department
+            join_on_condition:
+              keyword: 'ON'
+              expression:
+              - column_reference:
+                - identifier: employee
+                - dot: .
+                - identifier: deptno
+              - comparison_operator: '='
+              - column_reference:
+                - identifier: department
+                - dot: .
+                - identifier: deptno
+- statement_terminator: ;
+- base:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          wildcard_expression:
+            wildcard_identifier:
+              star: '*'
+      from_clause:
+        keyword: FROM
+        from_expression:
+          from_expression_element:
+            table_expression:
+              table_reference:
+                identifier: employee
+            alias_expression:
+              identifier: ANTI
+          join_clause:
+            keyword: JOIN
+            from_expression_element:
+              table_expression:
+                table_reference:
+                  identifier: department
+            join_on_condition:
+              keyword: 'ON'
+              expression:
+              - column_reference:
+                - identifier: employee
+                - dot: .
+                - identifier: deptno
+              - comparison_operator: '='
+              - column_reference:
+                - identifier: department
+                - dot: .
+                - identifier: deptno
+- statement_terminator: ;
+- base:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          wildcard_expression:
+            wildcard_identifier:
+              star: '*'
+      from_clause:
+        keyword: FROM
+        from_expression:
+          from_expression_element:
+            table_expression:
+              table_reference:
+                identifier: employee
+          join_clause:
+          - keyword: LEFT
+          - keyword: SEMI
+          - keyword: JOIN
+          - from_expression_element:
+              table_expression:
+                table_reference:
+                  identifier: department
+          - join_on_condition:
+              keyword: 'ON'
+              expression:
+              - column_reference:
+                - identifier: employee
+                - dot: .
+                - identifier: deptno
+              - comparison_operator: '='
+              - column_reference:
+                - identifier: department
+                - dot: .
+                - identifier: deptno
+- statement_terminator: ;
+- base:
+    select_statement:
+      select_clause:
+        keyword: SELECT
+        select_clause_element:
+          wildcard_expression:
+            wildcard_identifier:
+              star: '*'
+      from_clause:
+        keyword: FROM
+        from_expression:
+          from_expression_element:
+            table_expression:
+              table_reference:
+                identifier: employee
+          join_clause:
+          - keyword: LEFT
+          - keyword: ANTI
+          - keyword: JOIN
+          - from_expression_element:
+              table_expression:
+                table_reference:
+                  identifier: department
+          - join_on_condition:
+              keyword: 'ON'
+              expression:
+              - column_reference:
+                - identifier: employee
+                - dot: .
+                - identifier: deptno
+              - comparison_operator: '='
+              - column_reference:
+                - identifier: department
+                - dot: .
+                - identifier: deptno
+- statement_terminator: ;