Added aggregations and GROUP BY (#17)

tests/sqlite/test_range_select_from.cpp

@@ -0,0 +1,51 @@
+
+#include <gtest/gtest.h>
+
+#include <ranges>
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/sqlite.hpp>
+#include <vector>
+
+namespace test_range_select_from {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  int age;
+};
+
+TEST(sqlite, test_range_select_from) {
+  const auto people1 = std::vector<Person>(
+      {Person{
+           .id = 0, .first_name = "Homer", .last_name = "Simpson", .age = 45},
+       Person{.id = 1, .first_name = "Bart", .last_name = "Simpson", .age = 10},
+       Person{.id = 2, .first_name = "Lisa", .last_name = "Simpson", .age = 8},
+       Person{
+           .id = 3, .first_name = "Maggie", .last_name = "Simpson", .age = 0}});
+
+  using namespace sqlgen;
+
+  const auto people2 =
+      sqlgen::sqlite::connect()
+          .and_then(sqlgen::write(std::ref(people1)))
+          .and_then(select_from<Person>("first_name"_c) | order_by("id"_c))
+          .value();
+
+  using namespace std::ranges::views;
+
+  const auto first_names =
+      internal::collect::vector(people2 | transform([](const auto& _r) {
+                                  return rfl::get<"first_name">(_r.value());
+                                }));
+
+  EXPECT_EQ(first_names.at(0), "Homer");
+  EXPECT_EQ(first_names.at(1), "Bart");
+  EXPECT_EQ(first_names.at(2), "Lisa");
+  EXPECT_EQ(first_names.at(3), "Maggie");
+}
+
+}  // namespace test_range_select_from
+