Started to write serialize tests for WITH

include/sqlpp11/core/clause/cte.h

@@ -237,6 +237,11 @@ namespace sqlpp
   };
 
 #warning: is table? really? cte_ref needs to be a table, not sure about cte_t
+  template <typename NameTagProvider, typename Statement, typename... ColumnSpecs>
+  struct is_cte<cte_t<NameTagProvider, Statement, ColumnSpecs...>> : public std::true_type
+  {
+  };
+
   template <typename NameTagProvider, typename Statement, typename... ColumnSpecs>
   struct is_table<cte_t<NameTagProvider, Statement, ColumnSpecs...>> : public std::true_type
   {
@@ -259,11 +264,6 @@ namespace sqlpp
   template <typename NameTagProvider>
   struct cte_ref_t
   {
-    using _traits = make_traits<no_value_t, tag::is_alias, tag::is_cte>;
-    using _nodes = detail::type_vector<>;
-    using _required_ctes = detail::make_type_set_t<NameTagProvider>;
-    using _provided_tables = detail::type_set<NameTagProvider>;
-
     template <typename Statement>
     auto as(Statement statement) -> make_cte_t<NameTagProvider, Statement>
     {

include/sqlpp11/core/clause/with.h

@@ -115,8 +115,7 @@ namespace sqlpp
     auto operator()(Statement statement)
         -> new_statement_t<consistent_t, typename Statement::_policies_t, no_with_t, with_t<Expressions...>>
     {
-      // FIXME need checks here
-      //       check that no cte refers to any of the ctes to the right
+#warning: check that no cte refers to any of the ctes to the right
       return {statement, _data};
     }
   };
@@ -126,24 +125,23 @@ namespace sqlpp
   auto to_sql_string(Context& context, const with_data_t<Expressions...>& t) -> std::string
   {
     using T = with_data_t<Expressions...>;
-    // FIXME: If there is a recursive CTE, add a "RECURSIVE" here
-    context << " WITH ";
-    if (T::_is_recursive::value)
-    {
-      context << "RECURSIVE ";
-    }
-    tuple_to_sql_string(context, t._expressions, tuple_operand{", "});
-    context << ' ';
-    return context;
+#warning : If there is a recursive CTE, add a "RECURSIVE" here
+    return std::string("WITH ") + (T::_is_recursive::value ? "RECURSIVE " : "") +
+           tuple_to_sql_string(context, t._expressions, tuple_operand{", "}) + " ";
+  }
+
+  template <typename Context, typename... Expressions>
+  auto to_sql_string(Context& context, const blank_with_t<Expressions...>& t) -> std::string
+  {
+    return to_sql_string(context, t._data);
   }
 
   template <typename... Expressions>
   auto with(Expressions... cte) -> blank_with_t<Expressions...>
   {
-    static_assert(logic::all<is_cte_t<Expressions>::value...>::value,
+    static_assert(logic::all<is_cte<Expressions>::value...>::value,
                   "at least one expression in with is not a common table expression");
-    static_assert(logic::none<is_alias_t<Expressions>::value...>::value,
-                  "at least one expression in with is an incomplete common table expression");
+#warning: Need to test that cte_t::as yields a cte_ref and that cte_ref is not a cte
     return {{cte...}};
   }
 }  // namespace sqlpp

include/sqlpp11/core/type_traits.h

@@ -226,7 +226,6 @@ namespace sqlpp
   SQLPP_VALUE_TRAIT_GENERATOR(is_prepared_statement)
   SQLPP_VALUE_TRAIT_GENERATOR(is_union)
   SQLPP_VALUE_TRAIT_GENERATOR(is_with)
-  SQLPP_VALUE_TRAIT_GENERATOR(is_cte)
   SQLPP_VALUE_TRAIT_GENERATOR(is_noop)
   SQLPP_VALUE_TRAIT_GENERATOR(is_missing)
   SQLPP_VALUE_TRAIT_GENERATOR(is_pre_join)
@@ -592,4 +591,9 @@ namespace sqlpp
 
   template<typename T>
     struct is_result_clause : public std::false_type {};
+
+  template <typename T>
+  struct is_cte : public std::false_type
+  {
+  };
 }  // namespace sqlpp

tests/core/serialize/clause/CMakeLists.txt

@@ -51,4 +51,5 @@ create_test(union)
 create_test(update)
 create_test(update_set)
 create_test(where)
+create_test(with)
 

tests/core/serialize/clause/with.cpp

@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2024, Roland Bock
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "Sample.h"
+#include "../compare.h"
+#include <sqlpp11/sqlpp11.h>
+
+int main(int, char* [])
+{
+  const auto foo = test::TabFoo{};
+  const auto bar = test::TabBar{};
+
+  // No expression (not super useful).
+  SQLPP_COMPARE(cte(sqlpp::alias::x), "x");
+
+  // WITH Simple CTE: X AS SELECT
+  {
+    const auto x = cte(sqlpp::alias::x).as(select(foo.id).from(foo).unconditionally());
+    SQLPP_COMPARE(with(x), "WITH x AS (SELECT tab_foo.id FROM tab_foo) ");
+  }
+
+  // WITH Non-recursive union CTE: X AS SELECT ... UNION ALL SELECT ...
+  {
+    const auto x =
+        cte(sqlpp::alias::x)
+            .as(select(foo.id).from(foo).unconditionally().union_all(select(bar.id).from(bar).unconditionally()));
+    SQLPP_COMPARE(with(x), "WITH x AS (SELECT tab_foo.id FROM tab_foo UNION ALL SELECT tab_bar.id FROM tab_bar) ");
+  }
+
+  // WITH Recursive union CTE: X AS SELECT ... UNION ALL SELECT ... FROM X ...
+  {
+    const auto x_base = cte(sqlpp::alias::x).as(select(sqlpp::value(0).as(sqlpp::alias::a)));
+    const auto x = x_base.union_all(select((x_base.a + 1).as(sqlpp::alias::a)).from(x_base).where(x_base.a < 10));
+    using X = typename std::decay<decltype(x)>::type;
+    static_assert(X::_is_recursive, "");
+#warning: Need to test that recursive CTEs are detected as being recursive.
+    SQLPP_COMPARE(with(x), "WITH RECURSIVE x AS (SELECT 0 AS a UNION ALL SELECT (x.a + 1) AS a FROM x WHERE x.a < 10) ");
+  }
+
+  return 0;
+}