From cc34ab3e01cd2dcafed76da2879677085d5f8083 Mon Sep 17 00:00:00 2001
From: Eric Kidd <git@randomhacks.net>
Date: Thu, 9 Nov 2023 09:33:58 -0500
Subject: [PATCH] Figure out FIRST_VALUE & LAST_VALUE

---
 src/ast.rs                                    | 20 +++++++++++++++++++
 .../functions/windows/first_last_value.sql    |  6 ++----
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/ast.rs b/src/ast.rs
index 32679e1..1c542fe 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -1416,6 +1416,10 @@ pub enum WindowFrameStart {
         unbounded_token: Keyword,
         preceding_token: Keyword,
     },
+    CurrentRow {
+        current_token: Keyword,
+        row_token: PseudoKeyword,
+    },
 }
 
 /// A window frame end. Keep this simple for now.
@@ -1425,6 +1429,10 @@ pub enum WindowFrameEnd {
         current_token: Keyword,
         row_token: PseudoKeyword,
     },
+    UnboundedFollowing {
+        unbounded_token: Keyword,
+        following_token: Keyword,
+    },
 }
 
 /// Data types.
@@ -2544,6 +2552,12 @@ peg::parser! {
                     preceding_token,
                 }
             }
+            / current_token:k("CURRENT") row_token:pk("ROW") {
+                WindowFrameStart::CurrentRow {
+                    current_token,
+                    row_token,
+                }
+            }
 
         rule window_frame_end() -> WindowFrameEnd
             = current_token:k("CURRENT") row_token:pk("ROW") {
@@ -2552,6 +2566,12 @@ peg::parser! {
                     row_token,
                 }
             }
+            / unbounded_token:k("UNBOUNDED") following_token:k("FOLLOWING") {
+                WindowFrameEnd::UnboundedFollowing {
+                    unbounded_token,
+                    following_token,
+                }
+            }
 
         rule cast() -> Cast
             = cast_type:cast_type() paren1:p("(") expression:expression() as_token:k("AS") data_type:data_type() paren2:p(")") {
diff --git a/tests/sql/functions/windows/first_last_value.sql b/tests/sql/functions/windows/first_last_value.sql
index 8ab72e0..9681b76 100644
--- a/tests/sql/functions/windows/first_last_value.sql
+++ b/tests/sql/functions/windows/first_last_value.sql
@@ -1,6 +1,3 @@
--- pending: sqlite3 FIRST_VALUE, LAST_VALUE seem to require frames to work?
--- pending: trino FIRST_VALUE, LAST_VALUE seem to require frames to work?
-
 -- FIRST_VALUE, LAST_VALUE
 
 -- A fixture table for testing window functions.
@@ -22,7 +19,8 @@ CREATE OR REPLACE TABLE __result1 AS
 SELECT
     item,
     FIRST_VALUE(item) OVER (PARTITION BY category ORDER BY price) AS cheapest_alternative,
-    LAST_VALUE(item) OVER (PARTITION BY category ORDER BY price) AS most_expensive_alternative,
+    -- We need the RANGE frame here.
+    LAST_VALUE(item) OVER (PARTITION BY category ORDER BY price RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) AS most_expensive_alternative,
 FROM groceries;
 
 CREATE OR REPLACE TABLE __expected1 (