From d07f3a0e1747d9a87c8fabfd22dab5cae8f38eab Mon Sep 17 00:00:00 2001
From: Evgenij Ryazanov <katzyn@gmail.com>
Date: Sun, 28 Jan 2024 12:58:22 +0800
Subject: [PATCH 1/2] Fix references to CTEs from derived tables

---
 h2/src/docsrc/html/changelog.html             |  3 ++
 h2/src/main/org/h2/command/Parser.java        | 53 ++++++++-----------
 h2/src/main/org/h2/command/query/Query.java   | 31 ++++++++++-
 h2/src/main/org/h2/table/DerivedTable.java    |  6 +++
 .../org/h2/table/QueryExpressionTable.java    |  4 +-
 h2/src/test/org/h2/test/scripts/dml/with.sql  |  7 +++
 6 files changed, 70 insertions(+), 34 deletions(-)

diff --git a/h2/src/docsrc/html/changelog.html b/h2/src/docsrc/html/changelog.html
index 5555992b27..6b4bd9b649 100644
--- a/h2/src/docsrc/html/changelog.html
+++ b/h2/src/docsrc/html/changelog.html
@@ -21,6 +21,9 @@ <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
 <ul>
+<li>Issue #822: WITH clauses' column aliases are not maintained correctly when selecting from CTE from within a derived
+table
+</li>
 <li>Issue #910: Common Table Expressions (CTE) inside WITH should have their own identifier scope
 </li>
 <li>Issue #3981: Unexpected result when using trigonometric functions
diff --git a/h2/src/main/org/h2/command/Parser.java b/h2/src/main/org/h2/command/Parser.java
index acd027fedc..62803dddec 100644
--- a/h2/src/main/org/h2/command/Parser.java
+++ b/h2/src/main/org/h2/command/Parser.java
@@ -2478,27 +2478,37 @@ private Query parseQuery() {
 
     private Query parseQueryExpression() {
         int start = tokenIndex;
+        QueryScope outerQueryScope = queryScope;
         Query query;
         if (readIf(WITH)) {
-            queryScope = new QueryScope(queryScope);
+            queryScope = new QueryScope(outerQueryScope);
             try {
-                query = parseWith(start);
+                readIf("RECURSIVE");
+                // This WITH statement is not a temporary view - it is part of a persistent view
+                // as in CREATE VIEW abc AS WITH my_cte - this auto detects that condition.
+                boolean isTemporary = !session.isParsingCreateView();
+                do {
+                    parseSingleCommonTableExpression(isTemporary);
+                } while (readIf(COMMA));
+                query = parseQueryExpressionBodyAndEndOfQuery(start);
+                query.setPrepareAlways(true);
+                query.setNeverLazy(true);
                 query.setWithClause(queryScope.tableSubqeries);
             } finally {
-                queryScope = queryScope.parent;
+                queryScope = outerQueryScope;
             }
         } else {
-            query = parseQueryExpressionBodyAndEndOfQuery();
+            query = parseQueryExpressionBodyAndEndOfQuery(start);
         }
+        query.setOuterQueryScope(outerQueryScope);
         return query;
     }
 
-    private Query parseQueryExpressionBodyAndEndOfQuery() {
-        int start = tokenIndex;
-        Query command = parseQueryExpressionBody();
-        parseEndOfQuery(command);
-        setSQL(command, start);
-        return command;
+    private Query parseQueryExpressionBodyAndEndOfQuery(int start) {
+        Query query = parseQueryExpressionBody();
+        parseEndOfQuery(query);
+        setSQL(query, start);
+        return query;
     }
 
     private Query parseQueryExpressionBody() {
@@ -2661,9 +2671,10 @@ private void parseIsolationClause() {
 
     private Query parseQueryPrimary() {
         if (readIf(OPEN_PAREN)) {
-            Query command = parseQueryExpressionBodyAndEndOfQuery();
+            Query query = parseQueryExpressionBodyAndEndOfQuery(tokenIndex);
+            query.setOuterQueryScope(queryScope);
             read(CLOSE_PAREN);
-            return command;
+            return query;
         }
         int start = tokenIndex;
         if (readIf(SELECT)) {
@@ -6902,24 +6913,6 @@ private boolean isReservedFunctionName(String name) {
                 || BuiltinFunctions.isBuiltinFunction(database, name) && !database.isAllowBuiltinAliasOverride();
     }
 
-    private Query parseWith(int start) {
-        readIf("RECURSIVE");
-
-        // This WITH statement is not a temporary view - it is part of a persistent view
-        // as in CREATE VIEW abc AS WITH my_cte - this auto detects that condition.
-        final boolean isTemporary = !session.isParsingCreateView();
-
-        do {
-            parseSingleCommonTableExpression(isTemporary);
-        } while (readIf(COMMA));
-
-        Query query = parseQueryExpressionBodyAndEndOfQuery();
-        query.setPrepareAlways(true);
-        query.setNeverLazy(true);
-        setSQL(query, start);
-        return query;
-    }
-
     private void parseSingleCommonTableExpression(boolean isTemporary) {
         String cteViewName = readIdentifierWithSchema();
         Schema schema = getSchema();
diff --git a/h2/src/main/org/h2/command/query/Query.java b/h2/src/main/org/h2/command/query/Query.java
index ae2ecf72df..481864c1d9 100644
--- a/h2/src/main/org/h2/command/query/Query.java
+++ b/h2/src/main/org/h2/command/query/Query.java
@@ -16,6 +16,7 @@
 import org.h2.api.ErrorCode;
 import org.h2.command.CommandInterface;
 import org.h2.command.Prepared;
+import org.h2.command.QueryScope;
 import org.h2.engine.Database;
 import org.h2.engine.DbObject;
 import org.h2.engine.SessionLocal;
@@ -155,6 +156,14 @@ static final class OffsetFetch {
 
     boolean isPrepared;
 
+    /**
+     * The outer scope of this query.
+     */
+    private QueryScope outerQueryScope;
+
+    /**
+     * The WITH clause of this query.
+     */
     private LinkedHashMap<String, Table> withClause;
 
     Query(SessionLocal session) {
@@ -863,10 +872,30 @@ public final long getMaxDataModificationId() {
         return Math.max(visitor.getMaxDataModificationId(), session.getSnapshotDataModificationId());
     }
 
+    /**
+     * Returns the scope of the outer query.
+     *
+     * @return the scope of the outer query
+     */
+    public QueryScope getOuterQueryScope() {
+        return outerQueryScope;
+    }
+
+    /**
+     * Sets the scope of the outer query.
+     *
+     * @param outerQueryScope
+     *            the scope of the outer query
+     */
+    public void setOuterQueryScope(QueryScope outerQueryScope) {
+        this.outerQueryScope = outerQueryScope;
+    }
+
     /**
      * Sets the WITH clause of this query.
      *
-     * @param withClause the WITH clause of this query
+     * @param withClause
+     *            the WITH clause of this query
      */
     public void setWithClause(LinkedHashMap<String, Table> withClause) {
         this.withClause = withClause;
diff --git a/h2/src/main/org/h2/table/DerivedTable.java b/h2/src/main/org/h2/table/DerivedTable.java
index 06a5e6d710..99152746d8 100644
--- a/h2/src/main/org/h2/table/DerivedTable.java
+++ b/h2/src/main/org/h2/table/DerivedTable.java
@@ -8,6 +8,7 @@
 import java.util.ArrayList;
 
 import org.h2.api.ErrorCode;
+import org.h2.command.QueryScope;
 import org.h2.command.query.Query;
 import org.h2.engine.SessionLocal;
 import org.h2.expression.ExpressionVisitor;
@@ -91,4 +92,9 @@ public StringBuilder getSQL(StringBuilder builder, int sqlFlags) {
         return StringUtils.indent(builder.append("(\n"), querySQL, 4, true).append(')');
     }
 
+    @Override
+    public QueryScope getQueryScope() {
+        return viewQuery.getOuterQueryScope();
+    }
+
 }
diff --git a/h2/src/main/org/h2/table/QueryExpressionTable.java b/h2/src/main/org/h2/table/QueryExpressionTable.java
index 05679469b7..cc30862773 100644
--- a/h2/src/main/org/h2/table/QueryExpressionTable.java
+++ b/h2/src/main/org/h2/table/QueryExpressionTable.java
@@ -322,8 +322,6 @@ public final void addDependencies(HashSet<DbObject> dependencies) {
      *
      * @return the scope of this table
      */
-    public QueryScope getQueryScope() {
-        return null;
-    }
+    public abstract QueryScope getQueryScope();
 
 }
diff --git a/h2/src/test/org/h2/test/scripts/dml/with.sql b/h2/src/test/org/h2/test/scripts/dml/with.sql
index fbb7ce8e38..4df28f8c7e 100644
--- a/h2/src/test/org/h2/test/scripts/dml/with.sql
+++ b/h2/src/test/org/h2/test/scripts/dml/with.sql
@@ -239,3 +239,10 @@ WITH T(X) AS (SELECT 1)
 > 2
 > 3
 > rows: 3
+
+WITH T1(F1, F2) AS (SELECT 1, 2)
+SELECT A1.F1, A1.F2 FROM (SELECT * FROM T1) A1;
+> F1 F2
+> -- --
+> 1  2
+> rows: 1

From 4505de36014068420cf436c16e37c33de8d4d804 Mon Sep 17 00:00:00 2001
From: Evgenij Ryazanov <katzyn@gmail.com>
Date: Sun, 28 Jan 2024 13:08:12 +0800
Subject: [PATCH 2/2] Allow empty column lists in with clause and views

---
 h2/src/docsrc/html/changelog.html                  |  2 ++
 h2/src/main/org/h2/command/Parser.java             |  8 +++++---
 h2/src/test/org/h2/test/scripts/ddl/createView.sql | 12 ++++++++++++
 h2/src/test/org/h2/test/scripts/dml/with.sql       | 13 +++++++++++++
 4 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/h2/src/docsrc/html/changelog.html b/h2/src/docsrc/html/changelog.html
index 6b4bd9b649..ae2c8dc629 100644
--- a/h2/src/docsrc/html/changelog.html
+++ b/h2/src/docsrc/html/changelog.html
@@ -21,6 +21,8 @@ <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
 <ul>
+<li>Issue #3987: Allow empty &lt;with column list&gt;
+</li>
 <li>Issue #822: WITH clauses' column aliases are not maintained correctly when selecting from CTE from within a derived
 table
 </li>
diff --git a/h2/src/main/org/h2/command/Parser.java b/h2/src/main/org/h2/command/Parser.java
index 62803dddec..1a11089a3d 100644
--- a/h2/src/main/org/h2/command/Parser.java
+++ b/h2/src/main/org/h2/command/Parser.java
@@ -1135,9 +1135,11 @@ private int parseSortType() {
 
     private String[] parseColumnList() {
         ArrayList<String> columns = Utils.newSmallArrayList();
-        do {
-            columns.add(readIdentifier());
-        } while (readIfMore());
+        if (!readIf(CLOSE_PAREN)) {
+            do {
+                columns.add(readIdentifier());
+            } while (readIfMore());
+        }
         return columns.toArray(new String[0]);
     }
 
diff --git a/h2/src/test/org/h2/test/scripts/ddl/createView.sql b/h2/src/test/org/h2/test/scripts/ddl/createView.sql
index 3e1dbb919c..e3371355d4 100644
--- a/h2/src/test/org/h2/test/scripts/ddl/createView.sql
+++ b/h2/src/test/org/h2/test/scripts/ddl/createView.sql
@@ -52,3 +52,15 @@ SELECT * FROM TEST_VIEW;
 
 DROP TABLE TEST CASCADE;
 > ok
+
+CREATE VIEW V() AS SELECT;
+> ok
+
+TABLE V;
+>
+>
+>
+> rows: 1
+
+DROP VIEW V;
+> ok
diff --git a/h2/src/test/org/h2/test/scripts/dml/with.sql b/h2/src/test/org/h2/test/scripts/dml/with.sql
index 4df28f8c7e..a1388731d3 100644
--- a/h2/src/test/org/h2/test/scripts/dml/with.sql
+++ b/h2/src/test/org/h2/test/scripts/dml/with.sql
@@ -246,3 +246,16 @@ SELECT A1.F1, A1.F2 FROM (SELECT * FROM T1) A1;
 > -- --
 > 1  2
 > rows: 1
+
+CREATE VIEW V AS
+WITH A AS (SELECT) TABLE A;
+> ok
+
+TABLE V;
+>
+>
+>
+> rows: 1
+
+DROP VIEW V;
+> ok