[Feature Request]: strcmp function

pkg/sql/plan/function/func_binary.go

@@ -2198,6 +2198,20 @@ func EndsWith(ivecs []*vector.Vector, result vector.FunctionResultWrapper, proc
 	return opBinaryBytesBytesToFixed[bool](ivecs, result, proc, length, bytes.HasSuffix, selectList)
 }
 
+func Strcmp(ivecs []*vector.Vector, result vector.FunctionResultWrapper, proc *process.Process, length int, _ *FunctionSelectList) (err error) {
+	return opBinaryStrStrToFixed[int8](ivecs, result, proc, length, strcmp, nil)
+}
+
+func strcmp(s1, s2 string) int8 {
+	if s1 == s2 {
+		return 0
+	}
+	if s1 < s2 {
+		return -1
+	}
+	return 1
+}
+
 // https://dev.mysql.com/doc/refman/8.0/en/encryption-functions.html#function_sha2
 func SHA2Func(args []*vector.Vector, result vector.FunctionResultWrapper, _ *process.Process, length int, selectList *FunctionSelectList) (err error) {
 	res := vector.MustFunctionResult[types.Varlena](result)

pkg/sql/plan/function/func_binary_test.go

@@ -2166,6 +2166,61 @@ func TestInstr(t *testing.T) {
 	}
 }
 
+// STRCMP
+func initStrcmpTestCase() []tcTemp {
+	cases := []struct {
+		s1    string
+		s2    string
+		wants int8
+	}{
+		{"", "", 0},
+		{"", "a", -1},
+		{"a", "", 1},
+		{"0", "0", 0},
+		{"0", "1", -1},
+		{"0", "-1", 1},
+		{"ab", "abc", -1},
+		{"abcd", "abc", 1},
+		{"abce", "abcd", 1},
+		{"abce", "abcda", 1},
+		{"我们", "我", 1},
+		{"我们", "wo", 1},
+		{"我们", "woo", 1},
+		{"我们", "我们", 0},
+		{"我 们", "我们", -1},
+		{"-ae", "我", -1},
+		{":=符号只允许在函数中使用，即只能在声明局部变量的时候使用，而var没有这个限制", "a b cd ", -1},
+		{"符号只允许在函数中使用，即只能在声明局部变量的时候使用，而var没有这个限制", "a b cd ", 1},
+		{"符号只允许在函数中使用，即只能在声明局部变量的时候使用，而var没有这个限制", "符号只允许在函数中使用，即只能在声明局部变量的时候使用，而var没有这个限制", 0},
+	}
+
+	var testInputs = make([]tcTemp, 0, len(cases))
+	for _, c := range cases {
+		testInputs = append(testInputs, tcTemp{
+			info: "test strcmp ",
+			inputs: []FunctionTestInput{
+				// Create a input entry <str, str>
+				NewFunctionTestInput(types.T_varchar.ToType(), []string{c.s1}, []bool{}),
+				NewFunctionTestInput(types.T_varchar.ToType(), []string{c.s2}, []bool{}),
+			},
+			expect: NewFunctionTestResult(types.T_int8.ToType(), false, []int8{c.wants}, []bool{}),
+		})
+	}
+
+	return testInputs
+}
+
+func TestStrcmp(t *testing.T) {
+	testCases := initStrcmpTestCase()
+
+	proc := testutil.NewProcess()
+	for _, tc := range testCases {
+		fcTC := NewFunctionTestCase(proc, tc.inputs, tc.expect, Strcmp)
+		s, info := fcTC.Run()
+		require.True(t, s, fmt.Sprintf("case is '%s', err info is '%s'", tc.info, info))
+	}
+}
+
 // Left
 func initLeftTestCase() []tcTemp {
 	cases := []struct {

pkg/sql/plan/function/function_id.go

@@ -200,6 +200,7 @@ const (
 	STARTSWITH
 	STDDEV_POP
 	STDDEV_SAMPLE
+	STRCMP
 	SUBSTR
 	SUM
 	SYSDATE
@@ -539,6 +540,7 @@ var functionIdRegister = map[string]int32{
 	"sin":                            SIN,
 	"sinh":                           SINH,
 	"space":                          SPACE,
+	"strcmp":                         STRCMP,
 	"tan":                            TAN,
 	"week":                           WEEK,
 	"weekday":                        WEEKDAY,

pkg/sql/plan/function/list_builtIn.go

@@ -1517,6 +1517,27 @@ var supportedStringBuiltIns = []FuncNew{
 		},
 	},
 
+	// function `strcmp`
+	{
+		functionId: STRCMP,
+		class:      plan.Function_STRICT,
+		layout:     STANDARD_FUNCTION,
+		checkFn:    fixedTypeMatch,
+
+		Overloads: []overload{
+			{
+				overloadId: 0,
+				args:       []types.T{types.T_varchar, types.T_varchar},
+				retType: func(parameters []types.Type) types.Type {
+					return types.T_int32.ToType()
+				},
+				newOp: func() executeLogicOfOverload {
+					return Strcmp
+				},
+			},
+		},
+	},
+
 	// function `prefix_eq`
 	{
 		functionId: PREFIX_EQ,