From a3712ceefd603ac12c1e4a6bb79e3f4cb37276e4 Mon Sep 17 00:00:00 2001
From: Loic Nageleisen <loic.nageleisen@gmail.com>
Date: Tue, 21 Nov 2017 11:14:45 +0100
Subject: [PATCH] Add support for SELECT without FROM

---
 lib/rebel/sql.rb | 7 ++++++-
 test/test_raw.rb | 4 ++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/rebel/sql.rb b/lib/rebel/sql.rb
index cda9ce9..9379fdc 100644
--- a/lib/rebel/sql.rb
+++ b/lib/rebel/sql.rb
@@ -180,7 +180,8 @@ module Rebel::SQL
 
     def select(*fields, from: nil, where: nil, inner: nil, left: nil, right: nil)
       raw <<-SQL
-      SELECT #{names(*fields)} FROM #{name(from)}
+      SELECT #{names(*fields)}
+      #{from?(from)}
       #{inner?(inner)}
       #{left?(left)}
       #{right?(right)}
@@ -329,6 +330,10 @@ module Rebel::SQL
       end.join(' AND ')
     end
 
+    def from?(from)
+      from ? "FROM #{name(from)}" : nil
+    end
+
     def where?(*clause)
       clause.any? ? "WHERE #{and_clause(*clause)}" : nil
     end
diff --git a/test/test_raw.rb b/test/test_raw.rb
index 26ed190..b19aee1 100644
--- a/test/test_raw.rb
+++ b/test/test_raw.rb
@@ -105,6 +105,10 @@ class TestRaw < Minitest::Test
     assert_str_equal(Rebel::SQL.select(Rebel::SQL.raw('*'), from: Rebel::SQL.name(:foo)).gsub(/\s+/, ' ').strip, 'SELECT * FROM "foo"')
   end
 
+  def test_select_without_from
+    assert_str_equal(Rebel::SQL.select(Rebel::SQL.raw('1')).strip, 'SELECT 1')
+  end
+
   def test_nested_select
     assert_str_equal(Rebel::SQL.select(Rebel::SQL.raw('*'), from: Rebel::SQL.name(:foo), where: Rebel::SQL.name(:bar).in(Rebel::SQL.select(Rebel::SQL.name(:bar), from: Rebel::SQL.name(:foo)))).gsub(/\s+/, ' ').strip, 'SELECT * FROM "foo" WHERE "bar" IN ( SELECT "bar" FROM "foo" )')
   end