SparkSQL: Mark AS as optional keyword for CTE & CTS

src/sqlfluff/dialects/dialect_ansi.py

@@ -2378,7 +2378,7 @@ class CTEDefinitionSegment(BaseSegment):
     match_grammar: Matchable = Sequence(
         Ref("SingleIdentifierGrammar"),
         Ref("CTEColumnList", optional=True),
-        "AS",
+        Ref.keyword("AS", optional=True),
         Bracketed(
             # Ephemeral here to subdivide the query.
             Ref("SelectableGrammar", ephemeral_name="SelectableGrammar")

src/sqlfluff/dialects/dialect_sparksql.py

@@ -1107,7 +1107,7 @@ class CreateTableStatementSegment(ansi.CreateTableStatementSegment):
         Dedent,
         # Create AS syntax:
         Sequence(
-            "AS",
+            Ref.keyword("AS", optional=True),
             OptionallyBracketed(Ref("SelectableGrammar")),
             optional=True,
         ),

test/fixtures/dialects/ansi/with_insert_statement_a.sql

@@ -1,3 +1,4 @@
+-- with insert statement with `AS` keyword
 WITH mycte AS (
     SELECT
         foo,
@@ -8,3 +9,15 @@ WITH mycte AS (
 
 INSERT INTO table2 (column1, column2, column3)
 VALUES ('value1', 'value2', 'value3');
+
+-- with statement without `AS` keyword
+WITH mycte (
+    SELECT
+        foo,
+        bar,
+        baz
+    FROM mytable1
+)
+
+INSERT INTO table2 (column1, column2, column3)
+VALUES ('value1', 'value2', 'value3');

test/fixtures/dialects/ansi/with_insert_statement_a.yml

@@ -3,9 +3,9 @@
 # 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: 901525959391d20d72328da170a5095362855cc7191616b96e2282176c97b876
+_hash: ef68a2a74be445c8c3d4fac7628a5039e825b39471a35a2190c7cfb2ed58e3d7
 file:
-  statement:
+- statement:
     with_compound_statement:
       keyword: WITH
       common_table_expression:
@@ -64,4 +64,63 @@ file:
           - expression:
               quoted_literal: "'value3'"
           - end_bracket: )
-  statement_terminator: ;
+- statement_terminator: ;
+- statement:
+    with_compound_statement:
+      keyword: WITH
+      common_table_expression:
+        naked_identifier: mycte
+        bracketed:
+          start_bracket: (
+          select_statement:
+            select_clause:
+            - keyword: SELECT
+            - select_clause_element:
+                column_reference:
+                  naked_identifier: foo
+            - comma: ','
+            - select_clause_element:
+                column_reference:
+                  naked_identifier: bar
+            - comma: ','
+            - select_clause_element:
+                column_reference:
+                  naked_identifier: baz
+            from_clause:
+              keyword: FROM
+              from_expression:
+                from_expression_element:
+                  table_expression:
+                    table_reference:
+                      naked_identifier: mytable1
+          end_bracket: )
+      insert_statement:
+      - keyword: INSERT
+      - keyword: INTO
+      - table_reference:
+          naked_identifier: table2
+      - bracketed:
+        - start_bracket: (
+        - column_reference:
+            naked_identifier: column1
+        - comma: ','
+        - column_reference:
+            naked_identifier: column2
+        - comma: ','
+        - column_reference:
+            naked_identifier: column3
+        - end_bracket: )
+      - values_clause:
+          keyword: VALUES
+          bracketed:
+          - start_bracket: (
+          - expression:
+              quoted_literal: "'value1'"
+          - comma: ','
+          - expression:
+              quoted_literal: "'value2'"
+          - comma: ','
+          - expression:
+              quoted_literal: "'value3'"
+          - end_bracket: )
+- statement_terminator: ;

test/fixtures/dialects/sparksql/create_table_select.sql

@@ -0,0 +1,6 @@
+-- create table select without `AS` keyword
+CREATE TABLE tab1 SELECT * FROM tab2;
+
+
+-- create table select with `AS` keyword
+CREATE TABLE tab1 AS SELECT * FROM tab2;

test/fixtures/dialects/sparksql/create_table_select.yml

@@ -0,0 +1,50 @@
+# 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: 0c638fbc846086000ecd6a0d36354551fe8ed4377abce53076ab6ab93b98bd53
+file:
+- statement:
+    create_table_statement:
+    - keyword: CREATE
+    - keyword: TABLE
+    - table_reference:
+        naked_identifier: tab1
+    - 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:
+                  naked_identifier: tab2
+- statement_terminator: ;
+- statement:
+    create_table_statement:
+    - keyword: CREATE
+    - keyword: TABLE
+    - table_reference:
+        naked_identifier: tab1
+    - keyword: AS
+    - 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:
+                  naked_identifier: tab2
+- statement_terminator: ;