From 3600ae8199bf52275dcec661deaab1011750d569 Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Thu, 25 Dec 2025 16:04:21 +0100
Subject: [PATCH 1/8] Made sure the .set(...) works for nullable values

---
 include/sqlgen/transpilation/to_sets.hpp   |  8 ++--
 tests/sqlite/test_update_with_optional.cpp | 50 ++++++++++++++++++++++
 2 files changed, 55 insertions(+), 3 deletions(-)
 create mode 100644 tests/sqlite/test_update_with_optional.cpp

diff --git a/include/sqlgen/transpilation/to_sets.hpp b/include/sqlgen/transpilation/to_sets.hpp
index 3a071f84..d1e6750e 100644
--- a/include/sqlgen/transpilation/to_sets.hpp
+++ b/include/sqlgen/transpilation/to_sets.hpp
@@ -15,6 +15,7 @@
 #include "all_columns_exist.hpp"
 #include "get_schema.hpp"
 #include "get_tablename.hpp"
+#include "remove_nullable_t.hpp"
 #include "to_condition.hpp"
 #include "to_sets.hpp"
 #include "to_value.hpp"
@@ -30,9 +31,10 @@ struct ToSet<T, Set<transpilation::Col<_name>, ToType>> {
   static_assert(
       all_columns_exist<T, transpilation::Col<_name>>(),
       "At least one column referenced in your SET query does not exist.");
-  static_assert(std::is_convertible_v<underlying_t<T, Col<_name>>,
-                                      underlying_t<T, Value<ToType>>>,
-                "Must be convertible.");
+  static_assert(
+      std::is_convertible_v<remove_nullable_t<underlying_t<T, Col<_name>>>,
+                            remove_nullable_t<underlying_t<T, Value<ToType>>>>,
+      "Must be convertible.");
 
   dynamic::Update::Set operator()(const auto& _set) const {
     return dynamic::Update::Set{
diff --git a/tests/sqlite/test_update_with_optional.cpp b/tests/sqlite/test_update_with_optional.cpp
new file mode 100644
index 00000000..66057b83
--- /dev/null
+++ b/tests/sqlite/test_update_with_optional.cpp
@@ -0,0 +1,50 @@
+#include <gtest/gtest.h>
+
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/sqlite.hpp>
+#include <vector>
+
+namespace test_update_with_optional {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  std::optional<int> age;
+};
+
+TEST(sqlite, test_update_with_optional) {
+  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},
+       Person{
+           .id = 4, .first_name = "Hugo", .last_name = "Simpson", .age = 10}});
+
+  const auto conn = sqlgen::sqlite::connect();
+
+  sqlgen::write(conn, people1);
+
+  using namespace sqlgen;
+  using namespace sqlgen::literals;
+
+  const auto query =
+      update<Person>("first_name"_c.set("last_name"_c), "age"_c.set(100)) |
+      where("first_name"_c == "Hugo");
+
+  query(conn).value();
+
+  const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
+
+  const std::string expected =
+      R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":45},{"id":1,"first_name":"Bart","last_name":"Simpson","age":10},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson","age":100}])";
+
+  EXPECT_EQ(rfl::json::write(people2), expected);
+}
+
+}  // namespace test_update_with_optional

From 943247cec354ac76de70d18b3211bcb7dcc9b5a4 Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Fri, 26 Dec 2025 10:55:30 +0100
Subject: [PATCH 2/8] Made sure that setting to NULL values works

---
 include/sqlgen/dynamic/Value.hpp           |  4 +++-
 include/sqlgen/transpilation/to_sets.hpp   |  7 +++----
 include/sqlgen/transpilation/to_value.hpp  | 14 +++++++++++++-
 src/sqlgen/duckdb/to_sql.cpp               |  3 +++
 src/sqlgen/mysql/to_sql.cpp                |  3 +++
 src/sqlgen/postgres/to_sql.cpp             |  3 +++
 src/sqlgen/sqlite/to_sql.cpp               |  3 +++
 tests/sqlite/test_update_with_optional.cpp | 16 +++++++++++-----
 8 files changed, 42 insertions(+), 11 deletions(-)

diff --git a/include/sqlgen/dynamic/Value.hpp b/include/sqlgen/dynamic/Value.hpp
index 586159ba..35eb6685 100644
--- a/include/sqlgen/dynamic/Value.hpp
+++ b/include/sqlgen/dynamic/Value.hpp
@@ -25,6 +25,8 @@ struct Integer {
   int64_t val;
 };
 
+struct Null {};
+
 struct String {
   std::string val;
 };
@@ -35,7 +37,7 @@ struct Timestamp {
 
 struct Value {
   using ReflectionType = rfl::TaggedUnion<"type", Duration, Boolean, Float,
-                                          Integer, String, Timestamp>;
+                                          Integer, Null, String, Timestamp>;
   const auto& reflection() const { return val; }
   ReflectionType val;
 };
diff --git a/include/sqlgen/transpilation/to_sets.hpp b/include/sqlgen/transpilation/to_sets.hpp
index d1e6750e..e95aa75b 100644
--- a/include/sqlgen/transpilation/to_sets.hpp
+++ b/include/sqlgen/transpilation/to_sets.hpp
@@ -31,10 +31,9 @@ struct ToSet<T, Set<transpilation::Col<_name>, ToType>> {
   static_assert(
       all_columns_exist<T, transpilation::Col<_name>>(),
       "At least one column referenced in your SET query does not exist.");
-  static_assert(
-      std::is_convertible_v<remove_nullable_t<underlying_t<T, Col<_name>>>,
-                            remove_nullable_t<underlying_t<T, Value<ToType>>>>,
-      "Must be convertible.");
+  static_assert(std::is_convertible_v<underlying_t<T, Value<ToType>>,
+                                      underlying_t<T, Col<_name>>>,
+                "Must be convertible.");
 
   dynamic::Update::Set operator()(const auto& _set) const {
     return dynamic::Update::Set{
diff --git a/include/sqlgen/transpilation/to_value.hpp b/include/sqlgen/transpilation/to_value.hpp
index 5ca5c556..a39a217c 100644
--- a/include/sqlgen/transpilation/to_value.hpp
+++ b/include/sqlgen/transpilation/to_value.hpp
@@ -4,9 +4,11 @@
 #include <rfl.hpp>
 #include <type_traits>
 
+#include "../dynamic/Type.hpp"
 #include "../dynamic/Value.hpp"
 #include "Value.hpp"
 #include "has_reflection_method.hpp"
+#include "is_nullable.hpp"
 
 namespace sqlgen::transpilation {
 
@@ -17,7 +19,17 @@ template <class T>
 struct ToValue {
   dynamic::Value operator()(const T& _t) const {
     using Type = std::remove_cvref_t<T>;
-    if constexpr (std::is_floating_point_v<Type>) {
+    if constexpr (is_nullable_v<Type>) {
+      if (!_t) {
+        return dynamic::Value{dynamic::Null{}};
+      }
+      return ToValue<std::remove_cvref_t<decltype(*_t)>>{}(*_t);
+
+    } else if constexpr (std::is_same_v<Type, std::nullopt_t> ||
+                         std::is_same_v<Type, std::nullptr_t>) {
+      return dynamic::Value{dynamic::Null{}};
+
+    } else if constexpr (std::is_floating_point_v<Type>) {
       return dynamic::Value{dynamic::Float{.val = static_cast<double>(_t)}};
 
     } else if constexpr (std::is_same_v<Type, bool>) {
diff --git a/src/sqlgen/duckdb/to_sql.cpp b/src/sqlgen/duckdb/to_sql.cpp
index 3769f544..034aaedb 100644
--- a/src/sqlgen/duckdb/to_sql.cpp
+++ b/src/sqlgen/duckdb/to_sql.cpp
@@ -145,6 +145,9 @@ std::string column_or_value_to_sql(
       return "INTERVAL '" + std::to_string(_v.val) + " " +
              rfl::enum_to_string(_v.unit) + "'";
 
+    } else if constexpr (std::is_same_v<Type, dynamic::Null>) {
+      return "NULL";
+
     } else if constexpr (std::is_same_v<Type, dynamic::Timestamp>) {
       return "to_timestamp(" + std::to_string(_v.seconds_since_unix) + ")";
 
diff --git a/src/sqlgen/mysql/to_sql.cpp b/src/sqlgen/mysql/to_sql.cpp
index 2346f91c..4683a78e 100644
--- a/src/sqlgen/mysql/to_sql.cpp
+++ b/src/sqlgen/mysql/to_sql.cpp
@@ -175,6 +175,9 @@ std::string column_or_value_to_sql(
     if constexpr (std::is_same_v<Type, dynamic::String>) {
       return "'" + escape_single_quote(_v.val) + "'";
 
+    } else if constexpr (std::is_same_v<Type, dynamic::Null>) {
+      return "NULL";
+
     } else if constexpr (std::is_same_v<Type, dynamic::Duration>) {
       const auto unit =
           _v.unit == dynamic::TimeUnit::milliseconds
diff --git a/src/sqlgen/postgres/to_sql.cpp b/src/sqlgen/postgres/to_sql.cpp
index d2a47778..534c6506 100644
--- a/src/sqlgen/postgres/to_sql.cpp
+++ b/src/sqlgen/postgres/to_sql.cpp
@@ -134,6 +134,9 @@ std::string column_or_value_to_sql(
       return "INTERVAL '" + std::to_string(_v.val) + " " +
              rfl::enum_to_string(_v.unit) + "'";
 
+    } else if constexpr (std::is_same_v<Type, dynamic::Null>) {
+      return "NULL";
+
     } else if constexpr (std::is_same_v<Type, dynamic::Timestamp>) {
       return "to_timestamp(" + std::to_string(_v.seconds_since_unix) + ")";
 
diff --git a/src/sqlgen/sqlite/to_sql.cpp b/src/sqlgen/sqlite/to_sql.cpp
index c93da219..1a53328d 100644
--- a/src/sqlgen/sqlite/to_sql.cpp
+++ b/src/sqlgen/sqlite/to_sql.cpp
@@ -136,6 +136,9 @@ std::string column_or_value_to_sql(
                  rfl::enum_to_string(_v.unit) + "'";
       }
 
+    } else if constexpr (std::is_same_v<Type, dynamic::Null>) {
+      return "NULL";
+
     } else if constexpr (std::is_same_v<Type, dynamic::Timestamp>) {
       return std::to_string(_v.seconds_since_unix);
 
diff --git a/tests/sqlite/test_update_with_optional.cpp b/tests/sqlite/test_update_with_optional.cpp
index 66057b83..ce3a40be 100644
--- a/tests/sqlite/test_update_with_optional.cpp
+++ b/tests/sqlite/test_update_with_optional.cpp
@@ -33,16 +33,22 @@ TEST(sqlite, test_update_with_optional) {
   using namespace sqlgen;
   using namespace sqlgen::literals;
 
-  const auto query =
-      update<Person>("first_name"_c.set("last_name"_c), "age"_c.set(100)) |
-      where("first_name"_c == "Hugo");
+  const auto query1 = update<Person>("first_name"_c.set("last_name"_c),
+                                     "age"_c.set(std::nullopt)) |
+                      where("first_name"_c == "Hugo");
 
-  query(conn).value();
+  const auto query2 =
+      update<Person>("age"_c.set(50)) | where("first_name"_c == "Homer");
+
+  const auto query3 = update<Person>("age"_c.set(std::optional<int>(11))) |
+                      where("first_name"_c == "Bart");
+
+  query1(conn).and_then(query2).and_then(query3).value();
 
   const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
 
   const std::string expected =
-      R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":45},{"id":1,"first_name":"Bart","last_name":"Simpson","age":10},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson","age":100}])";
+      R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";
 
   EXPECT_EQ(rfl::json::write(people2), expected);
 }

From a181fe8ab831dbe5e022ed2369de92f1e536e7ca Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Fri, 26 Dec 2025 10:59:22 +0100
Subject: [PATCH 3/8] Added more tests

---
 tests/duckdb/test_update_with_optional.cpp   | 56 ++++++++++++++++++
 tests/mysql/test_update_with_optional.cpp    | 62 ++++++++++++++++++++
 tests/postgres/test_update_with_optional.cpp | 62 ++++++++++++++++++++
 3 files changed, 180 insertions(+)
 create mode 100644 tests/duckdb/test_update_with_optional.cpp
 create mode 100644 tests/mysql/test_update_with_optional.cpp
 create mode 100644 tests/postgres/test_update_with_optional.cpp

diff --git a/tests/duckdb/test_update_with_optional.cpp b/tests/duckdb/test_update_with_optional.cpp
new file mode 100644
index 00000000..3b5dede3
--- /dev/null
+++ b/tests/duckdb/test_update_with_optional.cpp
@@ -0,0 +1,56 @@
+#include <gtest/gtest.h>
+
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/duckdb.hpp>
+#include <vector>
+
+namespace test_update_with_optional {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  std::optional<int> age;
+};
+
+TEST(duckdb, test_update_with_optional) {
+  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},
+       Person{
+           .id = 4, .first_name = "Hugo", .last_name = "Simpson", .age = 10}});
+
+  const auto conn = sqlgen::duckdb::connect();
+
+  sqlgen::write(conn, people1);
+
+  using namespace sqlgen;
+  using namespace sqlgen::literals;
+
+  const auto query1 = update<Person>("first_name"_c.set("last_name"_c),
+                                     "age"_c.set(std::nullopt)) |
+                      where("first_name"_c == "Hugo");
+
+  const auto query2 =
+      update<Person>("age"_c.set(50)) | where("first_name"_c == "Homer");
+
+  const auto query3 = update<Person>("age"_c.set(std::optional<int>(11))) |
+                      where("first_name"_c == "Bart");
+
+  query1(conn).and_then(query2).and_then(query3).value();
+
+  const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
+
+  const std::string expected =
+      R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";
+
+  EXPECT_EQ(rfl::json::write(people2), expected);
+}
+
+}  // namespace test_update_with_optional
diff --git a/tests/mysql/test_update_with_optional.cpp b/tests/mysql/test_update_with_optional.cpp
new file mode 100644
index 00000000..6be0cff9
--- /dev/null
+++ b/tests/mysql/test_update_with_optional.cpp
@@ -0,0 +1,62 @@
+#include <gtest/gtest.h>
+
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/mysql.hpp>
+#include <vector>
+
+namespace test_update_with_optional {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  std::optional<int> age;
+};
+
+TEST(mysql, test_update_with_optional) {
+  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},
+       Person{
+           .id = 4, .first_name = "Hugo", .last_name = "Simpson", .age = 10}});
+
+  const auto credentials = sqlgen::mysql::Credentials{.host = "localhost",
+                                                      .user = "sqlgen",
+                                                      .password = "password",
+                                                      .dbname = "mysql"};
+
+  const auto conn =
+      sqlgen::mysql::connect(credentials).and_then(drop<Person> | if_exists);
+
+  sqlgen::write(conn, people1);
+
+  using namespace sqlgen;
+  using namespace sqlgen::literals;
+
+  const auto query1 = update<Person>("first_name"_c.set("last_name"_c),
+                                     "age"_c.set(std::nullopt)) |
+                      where("first_name"_c == "Hugo");
+
+  const auto query2 =
+      update<Person>("age"_c.set(50)) | where("first_name"_c == "Homer");
+
+  const auto query3 = update<Person>("age"_c.set(std::optional<int>(11))) |
+                      where("first_name"_c == "Bart");
+
+  query1(conn).and_then(query2).and_then(query3).value();
+
+  const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
+
+  const std::string expected =
+      R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";
+
+  EXPECT_EQ(rfl::json::write(people2), expected);
+}
+
+}  // namespace test_update_with_optional
diff --git a/tests/postgres/test_update_with_optional.cpp b/tests/postgres/test_update_with_optional.cpp
new file mode 100644
index 00000000..16bbbb50
--- /dev/null
+++ b/tests/postgres/test_update_with_optional.cpp
@@ -0,0 +1,62 @@
+#include <gtest/gtest.h>
+
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/postgres.hpp>
+#include <vector>
+
+namespace test_update_with_optional {
+
+struct Person {
+  sqlgen::PrimaryKey<uint32_t> id;
+  std::string first_name;
+  std::string last_name;
+  std::optional<int> age;
+};
+
+TEST(postgres, test_update_with_optional) {
+  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},
+       Person{
+           .id = 4, .first_name = "Hugo", .last_name = "Simpson", .age = 10}});
+
+  const auto credentials = sqlgen::postgres::Credentials{.user = "postgres",
+                                                         .password = "password",
+                                                         .host = "localhost",
+                                                         .dbname = "postgres"};
+
+  const auto conn =
+      sqlgen::postgres::connect(credentials).and_then(drop<Person> | if_exists);
+
+  sqlgen::write(conn, people1);
+
+  using namespace sqlgen;
+  using namespace sqlgen::literals;
+
+  const auto query1 = update<Person>("first_name"_c.set("last_name"_c),
+                                     "age"_c.set(std::nullopt)) |
+                      where("first_name"_c == "Hugo");
+
+  const auto query2 =
+      update<Person>("age"_c.set(50)) | where("first_name"_c == "Homer");
+
+  const auto query3 = update<Person>("age"_c.set(std::optional<int>(11))) |
+                      where("first_name"_c == "Bart");
+
+  query1(conn).and_then(query2).and_then(query3).value();
+
+  const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
+
+  const std::string expected =
+      R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";
+
+  EXPECT_EQ(rfl::json::write(people2), expected);
+}
+
+}  // namespace test_update_with_optional

From bc9a38bea0aea33ad51e7a0773302acd429355d4 Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Fri, 26 Dec 2025 11:14:14 +0100
Subject: [PATCH 4/8] Fixed typo

---
 tests/mysql/test_update_with_optional.cpp    | 6 +++---
 tests/postgres/test_update_with_optional.cpp | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/tests/mysql/test_update_with_optional.cpp b/tests/mysql/test_update_with_optional.cpp
index 6be0cff9..9d39a8fc 100644
--- a/tests/mysql/test_update_with_optional.cpp
+++ b/tests/mysql/test_update_with_optional.cpp
@@ -31,14 +31,14 @@ TEST(mysql, test_update_with_optional) {
                                                       .password = "password",
                                                       .dbname = "mysql"};
 
+  using namespace sqlgen;
+  using namespace sqlgen::literals;
+
   const auto conn =
       sqlgen::mysql::connect(credentials).and_then(drop<Person> | if_exists);
 
   sqlgen::write(conn, people1);
 
-  using namespace sqlgen;
-  using namespace sqlgen::literals;
-
   const auto query1 = update<Person>("first_name"_c.set("last_name"_c),
                                      "age"_c.set(std::nullopt)) |
                       where("first_name"_c == "Hugo");
diff --git a/tests/postgres/test_update_with_optional.cpp b/tests/postgres/test_update_with_optional.cpp
index 16bbbb50..d6e3d78c 100644
--- a/tests/postgres/test_update_with_optional.cpp
+++ b/tests/postgres/test_update_with_optional.cpp
@@ -31,14 +31,14 @@ TEST(postgres, test_update_with_optional) {
                                                          .host = "localhost",
                                                          .dbname = "postgres"};
 
+  using namespace sqlgen;
+  using namespace sqlgen::literals;
+
   const auto conn =
       sqlgen::postgres::connect(credentials).and_then(drop<Person> | if_exists);
 
   sqlgen::write(conn, people1);
 
-  using namespace sqlgen;
-  using namespace sqlgen::literals;
-
   const auto query1 = update<Person>("first_name"_c.set("last_name"_c),
                                      "age"_c.set(std::nullopt)) |
                       where("first_name"_c == "Hugo");

From 392d0e0ec01003df2cbe059599ab2cbbc2085ebe Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Fri, 26 Dec 2025 11:31:29 +0100
Subject: [PATCH 5/8] Insert ORDER BY to make the tests more stable

---
 tests/duckdb/test_update_with_optional.cpp   | 3 ++-
 tests/mysql/test_update_with_optional.cpp    | 3 ++-
 tests/postgres/test_update_with_optional.cpp | 3 ++-
 tests/sqlite/test_update_with_optional.cpp   | 3 ++-
 4 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/tests/duckdb/test_update_with_optional.cpp b/tests/duckdb/test_update_with_optional.cpp
index 3b5dede3..37ebaeca 100644
--- a/tests/duckdb/test_update_with_optional.cpp
+++ b/tests/duckdb/test_update_with_optional.cpp
@@ -45,7 +45,8 @@ TEST(duckdb, test_update_with_optional) {
 
   query1(conn).and_then(query2).and_then(query3).value();
 
-  const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
+  const auto people2 =
+      (sqlgen::read<std::vector<Person>> | order_by("id_c"))(conn).value();
 
   const std::string expected =
       R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";
diff --git a/tests/mysql/test_update_with_optional.cpp b/tests/mysql/test_update_with_optional.cpp
index 9d39a8fc..18d3a51b 100644
--- a/tests/mysql/test_update_with_optional.cpp
+++ b/tests/mysql/test_update_with_optional.cpp
@@ -51,7 +51,8 @@ TEST(mysql, test_update_with_optional) {
 
   query1(conn).and_then(query2).and_then(query3).value();
 
-  const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
+  const auto people2 =
+      (sqlgen::read<std::vector<Person>> | order_by("id"_c))(conn).value();
 
   const std::string expected =
       R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";
diff --git a/tests/postgres/test_update_with_optional.cpp b/tests/postgres/test_update_with_optional.cpp
index d6e3d78c..1fe86714 100644
--- a/tests/postgres/test_update_with_optional.cpp
+++ b/tests/postgres/test_update_with_optional.cpp
@@ -51,7 +51,8 @@ TEST(postgres, test_update_with_optional) {
 
   query1(conn).and_then(query2).and_then(query3).value();
 
-  const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
+  const auto people2 =
+      (sqlgen::read<std::vector<Person>> | order_by("id"_c))(conn).value();
 
   const std::string expected =
       R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";
diff --git a/tests/sqlite/test_update_with_optional.cpp b/tests/sqlite/test_update_with_optional.cpp
index ce3a40be..6cae65de 100644
--- a/tests/sqlite/test_update_with_optional.cpp
+++ b/tests/sqlite/test_update_with_optional.cpp
@@ -45,7 +45,8 @@ TEST(sqlite, test_update_with_optional) {
 
   query1(conn).and_then(query2).and_then(query3).value();
 
-  const auto people2 = sqlgen::read<std::vector<Person>>(conn).value();
+  const auto people2 =
+      (sqlgen::read<std::vector<Person>> | order_by("id"_c))(conn).value();
 
   const std::string expected =
       R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";

From fb9ead6bb9d9a02ba3d34b59beef4b0e0f2c7fb3 Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Fri, 26 Dec 2025 11:43:00 +0100
Subject: [PATCH 6/8] Build dry tests only

---
 tests/mysql/test_update_with_optional.cpp    | 4 ++++
 tests/postgres/test_update_with_optional.cpp | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/tests/mysql/test_update_with_optional.cpp b/tests/mysql/test_update_with_optional.cpp
index 18d3a51b..df6fd23e 100644
--- a/tests/mysql/test_update_with_optional.cpp
+++ b/tests/mysql/test_update_with_optional.cpp
@@ -1,3 +1,5 @@
+#ifndef SQLGEN_BUILD_DRY_TESTS_ONLY
+
 #include <gtest/gtest.h>
 
 #include <rfl.hpp>
@@ -61,3 +63,5 @@ TEST(mysql, test_update_with_optional) {
 }
 
 }  // namespace test_update_with_optional
+
+#endif
diff --git a/tests/postgres/test_update_with_optional.cpp b/tests/postgres/test_update_with_optional.cpp
index 1fe86714..ec1f2e7d 100644
--- a/tests/postgres/test_update_with_optional.cpp
+++ b/tests/postgres/test_update_with_optional.cpp
@@ -1,3 +1,5 @@
+#ifndef SQLGEN_BUILD_DRY_TESTS_ONLY
+
 #include <gtest/gtest.h>
 
 #include <rfl.hpp>
@@ -61,3 +63,5 @@ TEST(postgres, test_update_with_optional) {
 }
 
 }  // namespace test_update_with_optional
+
+#endif

From 8fd346107743054953e068249654f26389fb170f Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Fri, 26 Dec 2025 11:50:03 +0100
Subject: [PATCH 7/8] Update the documentation

---
 docs/update.md | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/docs/update.md b/docs/update.md
index 802b9b9b..46c8d833 100644
--- a/docs/update.md
+++ b/docs/update.md
@@ -98,6 +98,37 @@ SET "first_name" = "last_name"
 WHERE "age" > 18;
 ```
 
+### Setting Nullable Values
+
+Columns can be set using std::optional<T> values. Passing std::nullopt will set the column to NULL in the database, and passing a std::optional<T> with a value will set the column to that value.
+
+```cpp
+using namespace sqlgen;
+using namespace sqlgen::literals;
+
+// set to NULL
+const auto query1 = update<Person>("age"_c.set(std::nullopt)) |
+                   where("first_name"_c == "Hugo");
+
+// set to a value
+const auto query2 = update<Person>("age"_c.set(std::optional<int>(11))) |
+                   where("first_name"_c == "Bart");
+
+query1(conn).and_then(query2).value();
+```
+
+This generates the following SQL:
+
+```sql
+UPDATE "Person"
+SET "age" = NULL
+WHERE "first_name" = 'Hugo';
+
+UPDATE "Person"
+SET "age" = 11
+WHERE "first_name" = 'Bart';
+```
+
 ## Example: Full Query Composition
 
 ```cpp

From 113a9278572f546b8af7e79b7d628ef58cd37a20 Mon Sep 17 00:00:00 2001
From: "Dr. Patrick Urbanke" <patrick@getml.com>
Date: Fri, 26 Dec 2025 12:05:06 +0100
Subject: [PATCH 8/8] Fixed final typo

---
 tests/duckdb/test_update_with_optional.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/duckdb/test_update_with_optional.cpp b/tests/duckdb/test_update_with_optional.cpp
index 37ebaeca..2dbd87d2 100644
--- a/tests/duckdb/test_update_with_optional.cpp
+++ b/tests/duckdb/test_update_with_optional.cpp
@@ -46,7 +46,7 @@ TEST(duckdb, test_update_with_optional) {
   query1(conn).and_then(query2).and_then(query3).value();
 
   const auto people2 =
-      (sqlgen::read<std::vector<Person>> | order_by("id_c"))(conn).value();
+      (sqlgen::read<std::vector<Person>> | order_by("id"_c))(conn).value();
 
   const std::string expected =
       R"([{"id":0,"first_name":"Homer","last_name":"Simpson","age":50},{"id":1,"first_name":"Bart","last_name":"Simpson","age":11},{"id":2,"first_name":"Lisa","last_name":"Simpson","age":8},{"id":3,"first_name":"Maggie","last_name":"Simpson","age":0},{"id":4,"first_name":"Simpson","last_name":"Simpson"}])";