From 0f67501da3f31046f1dab4f3f39e5eeda39e2ac7 Mon Sep 17 00:00:00 2001
From: Andrey Pyzhikov <5071@mail.ru>
Date: Fri, 21 Jan 2022 05:21:40 +0800
Subject: [PATCH 1/2] Added alias escaping in subquery

---
 system/Database/BaseBuilder.php            | 3 ++-
 tests/system/Database/Builder/FromTest.php | 8 ++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/system/Database/BaseBuilder.php b/system/Database/BaseBuilder.php
index 8bbaf764dcf1..a3fc6c7563d3 100644
--- a/system/Database/BaseBuilder.php
+++ b/system/Database/BaseBuilder.php
@@ -2767,9 +2767,10 @@ protected function buildSubquery($builder, bool $wrapped = false, string $alias
 
         if ($wrapped) {
             $subquery = '(' . $subquery . ')';
+            $alias    = trim($alias);
 
             if ($alias !== '') {
-                $subquery .= " AS {$alias}";
+                $subquery .= ' AS ' . ($this->db->protectIdentifiers ? $this->db->escapeIdentifiers($alias) : $alias);
             }
         }
 
diff --git a/tests/system/Database/Builder/FromTest.php b/tests/system/Database/Builder/FromTest.php
index fee171e9ca42..b0e3ee335035 100644
--- a/tests/system/Database/Builder/FromTest.php
+++ b/tests/system/Database/Builder/FromTest.php
@@ -103,19 +103,19 @@ public function testFromReset()
 
     public function testFromSubquery()
     {
-        $expectedSQL = 'SELECT * FROM (SELECT * FROM "users") AS alias';
+        $expectedSQL = 'SELECT * FROM (SELECT * FROM "users") AS "alias"';
         $subquery    = new BaseBuilder('users', $this->db);
         $builder     = $this->db->newQuery()->fromSubquery($subquery, 'alias');
 
         $this->assertSame($expectedSQL, str_replace("\n", ' ', $builder->getCompiledSelect()));
 
-        $expectedSQL = 'SELECT * FROM (SELECT "id", "name" FROM "users") AS users_1';
+        $expectedSQL = 'SELECT * FROM (SELECT "id", "name" FROM "users") AS "users_1"';
         $subquery    = (new BaseBuilder('users', $this->db))->select('id, name');
         $builder     = $this->db->newQuery()->fromSubquery($subquery, 'users_1');
 
         $this->assertSame($expectedSQL, str_replace("\n", ' ', $builder->getCompiledSelect()));
 
-        $expectedSQL = 'SELECT * FROM (SELECT * FROM "users") AS alias, "some_table"';
+        $expectedSQL = 'SELECT * FROM (SELECT * FROM "users") AS "alias", "some_table"';
         $subquery    = new BaseBuilder('users', $this->db);
         $builder     = $this->db->newQuery()->fromSubquery($subquery, 'alias')->from('some_table');
 
@@ -145,7 +145,7 @@ public function testFromSubqueryWithSQLSRV()
 
         $builder->fromSubquery($subquery, 'users_1');
 
-        $expectedSQL = 'SELECT * FROM "test"."dbo"."jobs", (SELECT * FROM "test"."dbo"."users") AS users_1';
+        $expectedSQL = 'SELECT * FROM "test"."dbo"."jobs", (SELECT * FROM "test"."dbo"."users") AS "users_1"';
 
         $this->assertSame($expectedSQL, str_replace("\n", ' ', $builder->getCompiledSelect()));
     }

From d8406d98edd1d60229c916519d8e76aaaa16d756 Mon Sep 17 00:00:00 2001
From: Andrey Pyzhikov <5071@mail.ru>
Date: Sat, 22 Jan 2022 09:17:54 +0800
Subject: [PATCH 2/2] Fix: Escaping subquery alias docs

Signed-off-by: Andrey Pyzhikov <5071@mail.ru>
---
 user_guide_src/source/database/query_builder.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/user_guide_src/source/database/query_builder.rst b/user_guide_src/source/database/query_builder.rst
index 84d70732488a..d21896e3c251 100755
--- a/user_guide_src/source/database/query_builder.rst
+++ b/user_guide_src/source/database/query_builder.rst
@@ -234,7 +234,7 @@ This is where we add a subquery to an existing table.::
     $builder  = $db->table('jobs')->fromSubquery($subquery, 'alias');
     $query = $builder->get();
 
-    // Produces: SELECT * FROM `jobs`, (SELECT * FROM `users`) AS alias
+    // Produces: SELECT * FROM `jobs`, (SELECT * FROM `users`) AS `alias`
 
 Use the ``$db->newQuery()`` method to make a subquery the main table.::
 
@@ -242,7 +242,7 @@ Use the ``$db->newQuery()`` method to make a subquery the main table.::
     $builder  = $db->newQuery()->fromSubquery($subquery, 't');
     $query = $builder->get();
 
-    // Produces: SELECT * FROM (SELECT `id`, `name` FROM users) AS t
+    // Produces: SELECT * FROM (SELECT `id`, `name` FROM users) AS `t`
 
 Join
 ====