Allow column_name AS alias as safe SQL string

activerecord/lib/active_record/connection_adapters/abstract/quoting.rb

@@ -159,6 +159,7 @@ module ActiveRecord
         \A
         (
           (?:\w+\.)?\w+
+          (?:(?:\s+AS)?\s+\w+)?
         )
         (?:\s*,\s*\g<1>)*
         \z

activerecord/lib/active_record/connection_adapters/mysql/quoting.rb

@@ -44,6 +44,7 @@ module ActiveRecord
           \A
           (
             (?:\w+\.|`\w+`\.)?(?:\w+|`\w+`)
+            (?:(?:\s+AS)?\s+(?:\w+|`\w+`))?
           )
           (?:\s*,\s*\g<1>)*
           \z

activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb

@@ -90,6 +90,7 @@ module ActiveRecord
           \A
           (
             (?:\w+\.|"\w+"\.)?(?:\w+|"\w+")(?:::\w+)?
+            (?:(?:\s+AS)?\s+(?:\w+|"\w+"))?
           )
           (?:\s*,\s*\g<1>)*
           \z

activerecord/lib/active_record/connection_adapters/sqlite3/quoting.rb

@@ -57,6 +57,7 @@ module ActiveRecord
           \A
           (
             (?:\w+\.|"\w+"\.)?(?:\w+|"\w+")
+            (?:(?:\s+AS)?\s+(?:\w+|"\w+"))?
           )
           (?:\s*,\s*\g<1>)*
           \z

activerecord/test/cases/unsafe_raw_sql_test.rb

@@ -223,6 +223,16 @@ class UnsafeRawSqlTest < ActiveRecord::TestCase
     assert_equal titles_expected, titles_disabled
   end
 
+  test "pluck: allows string column name with alias" do
+    titles_expected = Post.pluck(Arel.sql("title"))
+
+    titles_depr     = with_unsafe_raw_sql_deprecated { Post.pluck("title AS posts_title") }
+    titles_disabled = with_unsafe_raw_sql_disabled   { Post.pluck("title AS posts_title") }
+
+    assert_equal titles_expected, titles_depr
+    assert_equal titles_expected, titles_disabled
+  end
+
   test "pluck: allows symbol column name" do
     titles_expected = Post.pluck(Arel.sql("title"))