support builtin function right

duckdb · May 6, 2020 · 12b0bf1 · 12b0bf1
1 parent dd173f2
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diff --git a/src/function/scalar/string/left_right.cpp b/src/function/scalar/string/left_right.cpp
@@ -35,4 +35,34 @@ void LeftFun::RegisterFunction(BuiltinFunctions &set) {
 	set.AddFunction(ScalarFunction("left", {SQLType::VARCHAR, SQLType::BIGINT}, SQLType::VARCHAR, left_function));
 }
 
+static string_t right_scalar_function(Vector &result, const string_t str, int64_t pos, unique_ptr<char[]> &output,
+                                      idx_t &current_len) {
+	int64_t num_characters = LengthFun::Length<string_t, int64_t>(str);
+	if (pos >= 0) {
+		int64_t len = std::min(num_characters, pos);
+		int64_t start = num_characters - len + 1;
+		return SubstringFun::substring_scalar_function(result, str, start, len, output, current_len);
+	}
+
+	int64_t len = num_characters - std::min(num_characters, -pos);
+	int64_t start = num_characters - len + 1;
+	return SubstringFun::substring_scalar_function(result, str, start, len, output, current_len);
+}
+
+static void right_function(DataChunk &args, ExpressionState &state, Vector &result) {
+	assert(args.column_count() == 2 && args.data[0].type == TypeId::VARCHAR && args.data[1].type == TypeId::INT64);
+	auto &str_vec = args.data[0];
+	auto &pos_vec = args.data[1];
+	idx_t current_len = 0;
+	unique_ptr<char[]> output;
+
+	BinaryExecutor::Execute<string_t, int64_t, string_t>(
+	    str_vec, pos_vec, result, args.size(),
+	    [&](string_t str, int64_t pos) { return right_scalar_function(result, str, pos, output, current_len); });
+}
+
+void RightFun::RegisterFunction(BuiltinFunctions &set) {
+	set.AddFunction(ScalarFunction("right", {SQLType::VARCHAR, SQLType::BIGINT}, SQLType::VARCHAR, right_function));
+}
+
 } // namespace duckdb
diff --git a/src/function/scalar/string_functions.cpp b/src/function/scalar/string_functions.cpp
@@ -16,6 +16,7 @@ void BuiltinFunctions::RegisterStringFunctions() {
 	Register<LpadFun>();
 	Register<LtrimFun>();
 	Register<LeftFun>();
+	Register<RightFun>();
 	Register<PrintfFun>();
 	Register<RegexpFun>();
 	Register<SubstringFun>();

diff --git a/src/include/duckdb/function/scalar/string_functions.hpp b/src/include/duckdb/function/scalar/string_functions.hpp
@@ -80,6 +80,10 @@ struct LeftFun {
 	static void RegisterFunction(BuiltinFunctions &set);
 };
 
+struct RightFun {
+	static void RegisterFunction(BuiltinFunctions &set);
+};
+
 struct RegexpFun {
 	static void RegisterFunction(BuiltinFunctions &set);
 };

diff --git a/test/sql/function/test_stringfunctions.cpp b/test/sql/function/test_stringfunctions.cpp
@@ -548,6 +548,92 @@ TEST_CASE("LEFT test", "[function]") {
 	REQUIRE(CHECK_COLUMN(result, 0, {"", "", ""}));
 }
 
+TEST_CASE("RIGHT test", "[function]") {
+	unique_ptr<QueryResult> result;
+	DuckDB db(nullptr);
+	Connection con(db);
+	con.EnableQueryVerification();
+
+	// test RIGHT on positive positions
+	result = con.Query("SELECT RIGHT('abcd', 0), RIGHT('abc', 1), RIGHT('abc', 2), RIGHT('abc', 3), RIGHT('abc', 4)");
+	REQUIRE(CHECK_COLUMN(result, 0, {""}));
+	REQUIRE(CHECK_COLUMN(result, 1, {"c"}));
+	REQUIRE(CHECK_COLUMN(result, 2, {"bc"}));
+	REQUIRE(CHECK_COLUMN(result, 3, {"abc"}));
+	REQUIRE(CHECK_COLUMN(result, 4, {"abc"}));
+
+	result = con.Query(
+	    "SELECT RIGHT('🦆ab', 0), RIGHT('🦆ab', 1), RIGHT('🦆ab', 2), RIGHT('🦆ab', 3), RIGHT('🦆ab', 4)");
+	REQUIRE(CHECK_COLUMN(result, 0, {""}));
+	REQUIRE(CHECK_COLUMN(result, 1, {"b"}));
+	REQUIRE(CHECK_COLUMN(result, 2, {"ab"}));
+	REQUIRE(CHECK_COLUMN(result, 3, {"🦆ab"}));
+	REQUIRE(CHECK_COLUMN(result, 4, {"🦆ab"}));
+
+	result = con.Query(
+	    "SELECT RIGHT('🦆🤦S̈', 0), RIGHT('🦆🤦S̈', 1), RIGHT('🦆🤦S̈', 2), RIGHT('🦆🤦S̈', 3)");
+	REQUIRE(CHECK_COLUMN(result, 0, {""}));
+	REQUIRE(CHECK_COLUMN(result, 1, {"S̈"}));
+	REQUIRE(CHECK_COLUMN(result, 2, {"🤦S̈"}));
+	REQUIRE(CHECK_COLUMN(result, 3, {"🦆🤦S̈"}));
+
+	// test RIGHT on negative positions
+	result =
+	    con.Query("SELECT RIGHT('abcd', 0), RIGHT('abc', -1), RIGHT('abc', -2), RIGHT('abc', -3), RIGHT('abc', -4)");
+	REQUIRE(CHECK_COLUMN(result, 0, {""}));
+	REQUIRE(CHECK_COLUMN(result, 1, {"bc"}));
+	REQUIRE(CHECK_COLUMN(result, 2, {"c"}));
+	REQUIRE(CHECK_COLUMN(result, 3, {""}));
+	REQUIRE(CHECK_COLUMN(result, 4, {""}));
+
+	result = con.Query("SELECT RIGHT('🦆ab', 0), RIGHT('🦆ab', -1), RIGHT('🦆ab', -2), RIGHT('🦆ab', -3), "
+	                   "RIGHT('🦆ab', -4)");
+	REQUIRE(CHECK_COLUMN(result, 0, {""}));
+	REQUIRE(CHECK_COLUMN(result, 1, {"ab"}));
+	REQUIRE(CHECK_COLUMN(result, 2, {"b"}));
+	REQUIRE(CHECK_COLUMN(result, 3, {""}));
+	REQUIRE(CHECK_COLUMN(result, 4, {""}));
+
+	result = con.Query(
+	    "SELECT RIGHT('🦆🤦S̈', 0), RIGHT('🦆🤦S̈', -1), RIGHT('🦆🤦S̈', -2), RIGHT('🦆🤦S̈', -3)");
+	REQUIRE(CHECK_COLUMN(result, 0, {""}));
+	REQUIRE(CHECK_COLUMN(result, 1, {"🤦S̈"}));
+	REQUIRE(CHECK_COLUMN(result, 2, {"S̈"}));
+	REQUIRE(CHECK_COLUMN(result, 3, {""}));
+
+	// test RIGHT on NULL values
+	result = con.Query("SELECT RIGHT(NULL, 0), RIGHT('abc', NULL), RIGHT(NULL, NULL)");
+	REQUIRE(CHECK_COLUMN(result, 0, {""}));
+	REQUIRE(CHECK_COLUMN(result, 1, {""}));
+	REQUIRE(CHECK_COLUMN(result, 2, {""}));
+
+	result = con.Query("SELECT RIGHT(NULL, 0), RIGHT('🦆ab', NULL), RIGHT(NULL, NULL)");
+	REQUIRE(CHECK_COLUMN(result, 0, {""}));
+	REQUIRE(CHECK_COLUMN(result, 1, {""}));
+	REQUIRE(CHECK_COLUMN(result, 2, {""}));
+
+	// test on tables
+	REQUIRE_NO_FAIL(con.Query("DROP TABLE IF EXISTS strings"));
+	REQUIRE_NO_FAIL(con.Query("CREATE TABLE strings(a STRING, b BIGINT)"));
+	REQUIRE_NO_FAIL(
+	    con.Query("INSERT INTO STRINGS VALUES ('abcd', 0), ('abc', 1), ('abc', 2), ('abc', 3), ('abc', 4)"));
+	result = con.Query("SELECT RIGHT(a, b) FROM strings");
+	REQUIRE(CHECK_COLUMN(result, 0, {"", "c", "bc", "abc", "abc"}));
+
+	REQUIRE_NO_FAIL(con.Query("DROP TABLE IF EXISTS strings"));
+	REQUIRE_NO_FAIL(con.Query("CREATE TABLE strings(a STRING, b BIGINT)"));
+	REQUIRE_NO_FAIL(
+	    con.Query("INSERT INTO STRINGS VALUES ('abcd', 0), ('abc', -1), ('abc', -2), ('abc', -3), ('abc', -4)"));
+	result = con.Query("SELECT RIGHT(a, b) FROM strings");
+	REQUIRE(CHECK_COLUMN(result, 0, {"", "bc", "c", "", ""}));
+
+	REQUIRE_NO_FAIL(con.Query("DROP TABLE IF EXISTS strings"));
+	REQUIRE_NO_FAIL(con.Query("CREATE TABLE strings(a STRING, b BIGINT)"));
+	REQUIRE_NO_FAIL(con.Query("INSERT INTO STRINGS VALUES (NULL, 0), ('abc', NULL), (NULL, NULL)"));
+	result = con.Query("SELECT RIGHT(a, b) FROM strings");
+	REQUIRE(CHECK_COLUMN(result, 0, {"", "", ""}));
+}
+
 TEST_CASE("BIT_LENGTH test", "[function]") {
 	unique_ptr<QueryResult> result;
 	DuckDB db(nullptr);