Merge pull request #1294 from tunetheweb/empty-over-window-specification

Support empty OVER() clause in Window Specification
sqlfluff · Aug 17, 2021 · 3005983 · 3005983
2 parents 00fca3a + 59f0f86
commit 3005983
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Showing 4 changed files with 29 additions and 5 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added
+- Added support for empty WINDOWS specificiations [#1293](https://github.com/sqlfluff/sqlfluff/pull/1293)
 ### Changed
 - Fix typo in the in the wild page [#1285](https://github.com/sqlfluff/sqlfluff/pull/1285)
 

diff --git a/src/sqlfluff/dialects/dialect_ansi.py b/src/sqlfluff/dialects/dialect_ansi.py
@@ -845,15 +845,15 @@ class OverClauseSegment(BaseSegment):
         OneOf(
             Ref("SingleIdentifierGrammar"),  # Window name
             Bracketed(
-                Ref("WindowSpecificationSegment"),
+                Ref("WindowSpecificationSegment", optional=True),
             ),
         ),
     )
 
 
 @ansi_dialect.segment()
 class WindowSpecificationSegment(BaseSegment):
-    """Window specification, e.g. OVER() or named window."""
+    """Window specification within OVER(...)."""
 
     type = "window_specification"
     match_grammar = Sequence(

diff --git a/test/fixtures/parser/ansi/select_named_window_with_parentheses.sql b/test/fixtures/parser/ansi/select_named_window_with_parentheses.sql
@@ -1,5 +1,6 @@
 SELECT
-    NTH_VALUE(bar, 1) OVER(w1) AS baz
+    NTH_VALUE(bar, 1) OVER(w1) AS baz,
+    NTH_VALUE(bar, 1) OVER() AS foo
 FROM t
 WINDOW w1 AS (
     PARTITION BY

diff --git a/test/fixtures/parser/ansi/select_named_window_with_parentheses.yml b/test/fixtures/parser/ansi/select_named_window_with_parentheses.yml
@@ -2,8 +2,8 @@ file:
   statement:
     select_statement:
       select_clause:
-        keyword: SELECT
-        select_clause_element:
+      - keyword: SELECT
+      - select_clause_element:
           function:
             function_name:
               function_name_identifier: NTH_VALUE
@@ -26,6 +26,28 @@ file:
           alias_expression:
             keyword: AS
             identifier: baz
+      - comma: ','
+      - select_clause_element:
+          function:
+            function_name:
+              function_name_identifier: NTH_VALUE
+            bracketed:
+            - start_bracket: (
+            - expression:
+                column_reference:
+                  identifier: bar
+            - comma: ','
+            - expression:
+                literal: '1'
+            - end_bracket: )
+            over_clause:
+              keyword: OVER
+              bracketed:
+                start_bracket: (
+                end_bracket: )
+          alias_expression:
+            keyword: AS
+            identifier: foo
       from_clause:
         keyword: FROM
         from_expression: