From 871f9478e3640a6dbf866ed62842241af0becf1f Mon Sep 17 00:00:00 2001
From: Herwin Weststrate <herwinw@herwinw.nl>
Date: Wed, 24 Oct 2018 09:53:23 +0200
Subject: [PATCH 1/3] Unit test for COPY with subquery

---
 spec/lib/pg_query/deparse_spec.rb | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/spec/lib/pg_query/deparse_spec.rb b/spec/lib/pg_query/deparse_spec.rb
index bf4dcb2f..b61a56d7 100644
--- a/spec/lib/pg_query/deparse_spec.rb
+++ b/spec/lib/pg_query/deparse_spec.rb
@@ -1116,6 +1116,12 @@
 
         it { is_expected.to eq oneline_query }
       end
+
+      context 'SUBQUERY' do
+        let(:query) { 'COPY (SELECT 1 FROM "foo") TO STDOUT' }
+
+        it { is_expected.to eq oneline_query }
+      end
     end
 
     context 'DO' do

From 3bac10486f140a1b5d08b817f7e6f9a635bbbd08 Mon Sep 17 00:00:00 2001
From: Herwin Weststrate <herwinw@herwinw.nl>
Date: Wed, 24 Oct 2018 09:56:12 +0200
Subject: [PATCH 2/3] Add subquery to COPY statement

Still needs refactoring to keep Rubocop satisfied.
---
 lib/pg_query/deparse.rb | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/pg_query/deparse.rb b/lib/pg_query/deparse.rb
index b7d03766..6b6b89e1 100644
--- a/lib/pg_query/deparse.rb
+++ b/lib/pg_query/deparse.rb
@@ -658,7 +658,11 @@ def deparse_constraint(node) # rubocop:disable Metrics/CyclomaticComplexity
 
     def deparse_copy(node)
       output = ['COPY']
-      output << deparse_item(node['relation'])
+      if node.key?('relation')
+        output << deparse_item(node['relation'])
+      elsif node.key?('query')
+        output << "(#{deparse_item(node['query'])})"
+      end
       columns = node.fetch('attlist', []).map { |column| deparse_item(column) }
       output << "(#{columns.join(', ')})" unless columns.empty?
       output << (node['is_from'] ? 'FROM' : 'TO')

From 72e4f7d4d31c9c37c68b7e42bfe27c74407ffaf8 Mon Sep 17 00:00:00 2001
From: Herwin Weststrate <herwinw@herwinw.nl>
Date: Wed, 24 Oct 2018 10:00:32 +0200
Subject: [PATCH 3/3] Refactor deparse_copy

This keeps Rubocop satisfied
---
 lib/pg_query/deparse.rb | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/lib/pg_query/deparse.rb b/lib/pg_query/deparse.rb
index 6b6b89e1..760de418 100644
--- a/lib/pg_query/deparse.rb
+++ b/lib/pg_query/deparse.rb
@@ -667,14 +667,16 @@ def deparse_copy(node)
       output << "(#{columns.join(', ')})" unless columns.empty?
       output << (node['is_from'] ? 'FROM' : 'TO')
       output << 'PROGRAM' if node['is_program']
-      output << if node.key?('filename')
-                  "'#{node['filename']}'"
-                else
-                  node['is_from'] ? 'STDIN' : 'STDOUT'
-                end
+      output << deparse_copy_output(node)
       output.join(' ')
     end
 
+    def deparse_copy_output(node)
+      return "'#{node['filename']}'" if node.key?('filename')
+      return 'STDIN' if node['is_from']
+      'STDOUT'
+    end
+
     def deparse_create_function(node)
       output = []
       output << 'CREATE'