From c729387ab66b19acdff02f047660bdda8f75b343 Mon Sep 17 00:00:00 2001
From: rbock <rbock@eudoxos.de>
Date: Thu, 11 Apr 2019 11:30:25 +0200
Subject: [PATCH] Allow INSERT INTO from SELECT

---
 include/sqlpp11/insert_value_list.h | 26 +++++++++++++++-----------
 test_serializer/CustomQuery.cpp     | 20 ++++++++++++++++----
 tests/Insert.cpp                    |  6 ++++--
 3 files changed, 35 insertions(+), 17 deletions(-)

diff --git a/include/sqlpp11/insert_value_list.h b/include/sqlpp11/insert_value_list.h
index 10fe19e6..56c36104 100644
--- a/include/sqlpp11/insert_value_list.h
+++ b/include/sqlpp11/insert_value_list.h
@@ -627,17 +627,17 @@ namespace sqlpp
       context << " (";
       interpret_tuple(t._columns, ",", context);
       context << ")";
-      context << " VALUES ";
       bool first = true;
       for (const auto& row : t._insert_values)
       {
-        if (not first)
+        if (first)
         {
-          context << ',';
+          context << " VALUES ";
+          first = false;
         }
         else
         {
-          first = false;
+          context << ',';
         }
         context << '(';
         interpret_tuple(row, ",", context);
@@ -669,14 +669,18 @@ namespace sqlpp
           context << ',';
         }
         interpret_list(t._dynamic_columns, ',', context);
-        context << ") VALUES(";
-        interpret_tuple(t._values, ",", context);
-        if (sizeof...(Assignments) and not t._dynamic_values.empty())
-        {
-          context << ',';
-        }
-        interpret_list(t._dynamic_values, ',', context);
         context << ")";
+        if (sizeof...(Assignments) or not t._dynamic_values.empty())
+        {
+          context << " VALUES(";
+          interpret_tuple(t._values, ",", context);
+          if (sizeof...(Assignments) and not t._dynamic_values.empty())
+          {
+            context << ',';
+          }
+          interpret_list(t._dynamic_values, ',', context);
+          context << ")";
+        }
       }
       return context;
     }
diff --git a/test_serializer/CustomQuery.cpp b/test_serializer/CustomQuery.cpp
index 4c00aec5..f86a859d 100644
--- a/test_serializer/CustomQuery.cpp
+++ b/test_serializer/CustomQuery.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016-2016, Roland Bock
+ * Copyright (c) 2016-2019, Roland Bock
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modification,
@@ -31,15 +31,16 @@
 
 SQLPP_ALIAS_PROVIDER(pragma)
 
-int CustomQuery(int, char* [])
+int CustomQuery(int, char*[])
 {
   const auto foo = test::TabFoo{};
   const auto bar = test::TabBar{};
   auto db = MockDb{};
 
   // Unconditionally
-  compare(__LINE__, custom_query(sqlpp::select(), select_flags(sqlpp::distinct), select_columns(foo.omega), from(foo),
-                                 sqlpp::unconditionally()),
+  compare(__LINE__,
+          custom_query(sqlpp::select(), select_flags(sqlpp::distinct), select_columns(foo.omega), from(foo),
+                       sqlpp::unconditionally()),
           "SELECT  DISTINCT  tab_foo.omega  FROM tab_foo ");
 
   // A full select statement made individual clauses
@@ -68,5 +69,16 @@ int CustomQuery(int, char* [])
           custom_query(sqlpp::verbatim("PRAGMA user_version")).with_result_type_of(select(sqlpp::value(1).as(pragma))),
           " PRAGMA user_version");
 
+  // An insert from select for postgresql
+  const auto x = 17;
+  compare(__LINE__,
+          custom_query(insert_into(foo).columns(foo.omega),
+                       select(sqlpp::value(x).as(foo.omega))
+                           .from(foo)
+                           .where(not exists(select(foo.omega).from(foo).where(foo.omega == x)))),
+          "INSERT INTO tab_foo (omega) "
+          "SELECT 17 AS omega FROM tab_foo "
+          "WHERE (NOT EXISTS(SELECT tab_foo.omega FROM tab_foo WHERE (tab_foo.omega=17)))");
+
   return 0;
 }
diff --git a/tests/Insert.cpp b/tests/Insert.cpp
index a364fdce..34e3a48c 100644
--- a/tests/Insert.cpp
+++ b/tests/Insert.cpp
@@ -66,9 +66,11 @@ int Insert(int, char*[])
   multi_insert.values.add(t.gamma = true, t.beta = "cheesecake", t.delta = 1);
   multi_insert.values.add(t.gamma = sqlpp::default_value, t.beta = sqlpp::default_value,
                           t.delta = sqlpp::default_value);
-  multi_insert.values.add(t.gamma = sqlpp::value_or_null(true),
-                          t.beta = sqlpp::value_or_null("pie"),
+  multi_insert.values.add(t.gamma = sqlpp::value_or_null(true), t.beta = sqlpp::value_or_null("pie"),
                           t.delta = sqlpp::value_or_null<sqlpp::integer>(sqlpp::null));
+  printer.reset();
+  std::cerr << serialize(multi_insert, printer).str() << std::endl;
+
   auto i = dynamic_insert_into(db, t).dynamic_set();
   i.insert_list.add(t.beta = "kirschauflauf");
   printer.reset();