Added aggregations and GROUP BY (#17)

tests/sqlite/test_aggregations.cpp

@@ -0,0 +1,63 @@
+
+#include <gtest/gtest.h>
+
+#include <ranges>
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/sqlite.hpp>
+#include <vector>
+
+namespace test_aggregations {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  int age;
+};
+
+TEST(sqlite, test_aggregations) {
+  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;
+
+  struct Children {
+    int num_children;
+    int num_last_names;
+    double avg_age;
+    double max_age;
+    double min_age;
+    double sum_age;
+  };
+
+  const auto get_children =
+      select_from<Person>(
+          avg("age"_c).as<"avg_age">(), count().as<"num_children">(),
+          max("age"_c).as<"max_age">(), min("age"_c).as<"min_age">(),
+          sum("age"_c).as<"sum_age">(),
+          count_distinct("last_name"_c).as<"num_last_names">()) |
+      where("age"_c < 18) | to<Children>;
+
+  const auto children = sqlite::connect()
+                            .and_then(drop<Person> | if_exists)
+                            .and_then(write(std::ref(people1)))
+                            .and_then(get_children)
+                            .value();
+
+  EXPECT_EQ(children.num_children, 3);
+  EXPECT_EQ(children.num_last_names, 1);
+  EXPECT_EQ(children.avg_age, 6.0);
+  EXPECT_EQ(children.max_age, 10.0);
+  EXPECT_EQ(children.min_age, 0.0);
+  EXPECT_EQ(children.sum_age, 18.0);
+}
+
+}  // namespace test_aggregations
+

tests/sqlite/test_aggregations_with_nullable.cpp

@@ -0,0 +1,62 @@
+
+#include <gtest/gtest.h>
+
+#include <ranges>
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/sqlite.hpp>
+#include <vector>
+
+namespace test_aggregations_with_nullable {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  std::optional<double> age;
+};
+
+TEST(sqlite, test_aggregations_with_nullable) {
+  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"}});
+
+  using namespace sqlgen;
+
+  struct Children {
+    int num_children;
+    int num_last_names;
+    std::optional<double> avg_age;
+    std::optional<double> max_age;
+    std::optional<double> min_age;
+    std::optional<double> sum_age;
+  };
+
+  const auto get_children =
+      select_from<Person>(
+          avg("age"_c).as<"avg_age">(), count().as<"num_children">(),
+          max("age"_c).as<"max_age">(), min("age"_c).as<"min_age">(),
+          sum("age"_c).as<"sum_age">(),
+          count_distinct("last_name"_c).as<"num_last_names">()) |
+      where("age"_c < 18 or "age"_c.is_null()) | to<Children>;
+
+  const auto children = sqlite::connect()
+                            .and_then(drop<Person> | if_exists)
+                            .and_then(write(std::ref(people1)))
+                            .and_then(get_children)
+                            .value();
+
+  EXPECT_EQ(children.num_children, 3);
+  EXPECT_EQ(children.num_last_names, 1);
+  EXPECT_EQ(children.avg_age, 9.0);
+  EXPECT_EQ(children.max_age, 10.0);
+  EXPECT_EQ(children.min_age, 8.0);
+  EXPECT_EQ(children.sum_age, 18.0);
+}
+
+}  // namespace test_aggregations_with_nullable
+

tests/sqlite/test_group_by.cpp

@@ -0,0 +1,66 @@
+
+#include <gtest/gtest.h>
+
+#include <ranges>
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/sqlite.hpp>
+#include <vector>
+
+namespace test_group_by {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  int age;
+};
+
+TEST(sqlite, test_group_by) {
+  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;
+
+  struct Children {
+    std::string last_name;
+    int num_children;
+    int num_last_names;
+    double avg_age;
+    double max_age;
+    double min_age;
+    double sum_age;
+  };
+
+  const auto get_children =
+      select_from<Person>(
+          "last_name"_c, avg("age"_c).as<"avg_age">(),
+          count().as<"num_children">(), max("age"_c).as<"max_age">(),
+          min("age"_c).as<"min_age">(), sum("age"_c).as<"sum_age">(),
+          count_distinct("last_name"_c).as<"num_last_names">()) |
+      where("age"_c < 18) | group_by("last_name"_c) | to<std::vector<Children>>;
+
+  const auto children = sqlite::connect()
+                            .and_then(drop<Person> | if_exists)
+                            .and_then(write(std::ref(people1)))
+                            .and_then(get_children)
+                            .value();
+
+  EXPECT_EQ(children.size(), 1);
+  EXPECT_EQ(children.at(0).last_name, "Simpson");
+  EXPECT_EQ(children.at(0).num_children, 3);
+  EXPECT_EQ(children.at(0).num_last_names, 1);
+  EXPECT_EQ(children.at(0).avg_age, 6.0);
+  EXPECT_EQ(children.at(0).max_age, 10.0);
+  EXPECT_EQ(children.at(0).min_age, 0.0);
+  EXPECT_EQ(children.at(0).sum_age, 18.0);
+}
+
+}  // namespace test_group_by
+

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
+

tests/sqlite/test_range_select_from_with_to.cpp

@@ -0,0 +1,50 @@
+
+#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_with_to {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  int age;
+};
+
+TEST(sqlite, test_range_select_from_with_to) {
+  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;
+
+  struct FirstName {
+    std::string first_name;
+  };
+
+  const auto people2 =
+      sqlite::connect()
+          .and_then(drop<Person> | if_exists)
+          .and_then(write(std::ref(people1)))
+          .and_then(select_from<Person>("first_name"_c) | order_by("id"_c) |
+                    to<std::vector<FirstName>>)
+          .value();
+
+  EXPECT_EQ(people2.at(0).first_name, "Homer");
+  EXPECT_EQ(people2.at(1).first_name, "Bart");
+  EXPECT_EQ(people2.at(2).first_name, "Lisa");
+  EXPECT_EQ(people2.at(3).first_name, "Maggie");
+}
+
+}  // namespace test_range_select_from_with_to
+

tests/sqlite/test_to_select_from.cpp

@@ -2,7 +2,6 @@
 
 #include <sqlgen.hpp>
 #include <sqlgen/sqlite.hpp>
-#include <sqlgen/transpilation/to_select_from.hpp>
 
 namespace test_to_select_from {
 
@@ -15,7 +14,7 @@ struct TestTable {
 
 TEST(sqlite, test_to_select_from) {
   const auto select_from_stmt =
-      sqlgen::transpilation::to_select_from<TestTable>();
+      sqlgen::transpilation::read_to_select_from<TestTable>();
   const auto conn = sqlgen::sqlite::connect().value();
   const auto expected =
       R"(SELECT "field1", "field2", "id", "nullable" FROM "TestTable";)";