diff --git a/internal/proxy/plan_parser.go b/internal/proxy/plan_parser.go
index ae0d43edd4..5644105019 100644
--- a/internal/proxy/plan_parser.go
+++ b/internal/proxy/plan_parser.go
@@ -202,44 +202,38 @@ func isSameOrder(opStr1, opStr2 string) bool {
 	return isLess1 == isLess2
 }
 
-func getCompareOpType(opStr string, reverse bool) planpb.OpType {
-	type OpType = planpb.OpType
-	var op planpb.OpType
-
-	if !reverse {
-		switch opStr {
-		case "<":
+func getCompareOpType(opStr string, reverse bool) (op planpb.OpType) {
+	switch opStr {
+	case ">":
+		if reverse {
 			op = planpb.OpType_LessThan
-		case ">":
+		} else {
 			op = planpb.OpType_GreaterThan
-		case "<=":
-			op = planpb.OpType_LessEqual
-		case ">=":
-			op = planpb.OpType_GreaterEqual
-		case "==":
-			op = planpb.OpType_Equal
-		case "!=":
-			op = planpb.OpType_NotEqual
-		default:
-			op = planpb.OpType_Invalid
 		}
-	} else {
-		switch opStr {
-		case ">":
+	case "<":
+		if reverse {
+			op = planpb.OpType_GreaterThan
+		} else {
 			op = planpb.OpType_LessThan
-		case "<":
-			op = planpb.OpType_GreaterThan
-		case ">=":
-			op = planpb.OpType_LessEqual
-		case "<=":
-			op = planpb.OpType_GreaterEqual
-		case "==":
-			op = planpb.OpType_Equal
-		case "!=":
-			op = planpb.OpType_NotEqual
-		default:
-			op = planpb.OpType_Invalid
 		}
+	case ">=":
+		if reverse {
+			op = planpb.OpType_LessEqual
+		} else {
+			op = planpb.OpType_GreaterEqual
+		}
+	case "<=":
+		if reverse {
+			op = planpb.OpType_GreaterEqual
+		} else {
+			op = planpb.OpType_LessEqual
+		}
+	case "==":
+		op = planpb.OpType_Equal
+	case "!=":
+		op = planpb.OpType_NotEqual
+	default:
+		op = planpb.OpType_Invalid
 	}
 	return op
 }
@@ -283,10 +277,10 @@ func (pc *ParserContext) createCmpExpr(left, right ant_ast.Node, operator string
 	if boolNode := parseBoolNode(&right); boolNode != nil {
 		right = boolNode
 	}
-	idNodeLeft, leftIDNode := left.(*ant_ast.IdentifierNode)
-	idNodeRight, rightIDNode := right.(*ant_ast.IdentifierNode)
+	idNodeLeft, okLeft := left.(*ant_ast.IdentifierNode)
+	idNodeRight, okRight := right.(*ant_ast.IdentifierNode)
 
-	if leftIDNode && rightIDNode {
+	if okLeft && okRight {
 		leftField, err := pc.handleIdentifier(idNodeLeft)
 		if err != nil {
 			return nil, err
@@ -312,15 +306,15 @@ func (pc *ParserContext) createCmpExpr(left, right ant_ast.Node, operator string
 	}
 
 	var idNode *ant_ast.IdentifierNode
-	var isReversed bool
+	var reverse bool
 	var valueNode *ant_ast.Node
-	if leftIDNode {
+	if okLeft {
 		idNode = idNodeLeft
-		isReversed = false
+		reverse = false
 		valueNode = &right
-	} else if rightIDNode {
+	} else if okRight {
 		idNode = idNodeRight
-		isReversed = true
+		reverse = true
 		valueNode = &left
 	} else {
 		return nil, fmt.Errorf("compare expr has no identifier")
@@ -336,7 +330,7 @@ func (pc *ParserContext) createCmpExpr(left, right ant_ast.Node, operator string
 		return nil, err
 	}
 
-	op := getCompareOpType(operator, isReversed)
+	op := getCompareOpType(operator, reverse)
 	if op == planpb.OpType_Invalid {
 		return nil, fmt.Errorf("invalid binary operator(%s)", operator)
 	}
diff --git a/internal/proxy/plan_parser_test.go b/internal/proxy/plan_parser_test.go
index f51d9cf80b..4e0c6242f2 100644
--- a/internal/proxy/plan_parser_test.go
+++ b/internal/proxy/plan_parser_test.go
@@ -315,27 +315,66 @@ func TestExprFieldCompare_Str(t *testing.T) {
 	}
 }
 
-func Test_ParseBoolNode(t *testing.T) {
-	var nodeRaw1, nodeRaw2, nodeRaw3, nodeRaw4 ant_ast.Node
-	nodeRaw1 = &ant_ast.IdentifierNode{
-		Value: "True",
-	}
-	boolNode1 := parseBoolNode(&nodeRaw1)
-	assert.Equal(t, boolNode1.Value, true)
+func TestPlanParseAPIs(t *testing.T) {
+	t.Run("get compare op type", func(t *testing.T) {
+		var op planpb.OpType
+		var reverse bool
 
-	nodeRaw2 = &ant_ast.IdentifierNode{
-		Value: "False",
-	}
-	boolNode2 := parseBoolNode(&nodeRaw2)
-	assert.Equal(t, boolNode2.Value, false)
+		reverse = false
+		op = getCompareOpType(">", reverse)
+		assert.Equal(t, planpb.OpType_GreaterThan, op)
+		op = getCompareOpType(">=", reverse)
+		assert.Equal(t, planpb.OpType_GreaterEqual, op)
+		op = getCompareOpType("<", reverse)
+		assert.Equal(t, planpb.OpType_LessThan, op)
+		op = getCompareOpType("<=", reverse)
+		assert.Equal(t, planpb.OpType_LessEqual, op)
+		op = getCompareOpType("==", reverse)
+		assert.Equal(t, planpb.OpType_Equal, op)
+		op = getCompareOpType("!=", reverse)
+		assert.Equal(t, planpb.OpType_NotEqual, op)
+		op = getCompareOpType("*", reverse)
+		assert.Equal(t, planpb.OpType_Invalid, op)
 
-	nodeRaw3 = &ant_ast.IdentifierNode{
-		Value: "abcd",
-	}
-	assert.Nil(t, parseBoolNode(&nodeRaw3))
+		reverse = true
+		op = getCompareOpType(">", reverse)
+		assert.Equal(t, planpb.OpType_LessThan, op)
+		op = getCompareOpType(">=", reverse)
+		assert.Equal(t, planpb.OpType_LessEqual, op)
+		op = getCompareOpType("<", reverse)
+		assert.Equal(t, planpb.OpType_GreaterThan, op)
+		op = getCompareOpType("<=", reverse)
+		assert.Equal(t, planpb.OpType_GreaterEqual, op)
+		op = getCompareOpType("==", reverse)
+		assert.Equal(t, planpb.OpType_Equal, op)
+		op = getCompareOpType("!=", reverse)
+		assert.Equal(t, planpb.OpType_NotEqual, op)
+		op = getCompareOpType("*", reverse)
+		assert.Equal(t, planpb.OpType_Invalid, op)
+	})
 
-	nodeRaw4 = &ant_ast.BoolNode{
-		Value: true,
-	}
-	assert.Nil(t, parseBoolNode(&nodeRaw4))
+	t.Run("parse bool node", func(t *testing.T) {
+		var nodeRaw1, nodeRaw2, nodeRaw3, nodeRaw4 ant_ast.Node
+		nodeRaw1 = &ant_ast.IdentifierNode{
+			Value: "True",
+		}
+		boolNode1 := parseBoolNode(&nodeRaw1)
+		assert.Equal(t, boolNode1.Value, true)
+
+		nodeRaw2 = &ant_ast.IdentifierNode{
+			Value: "False",
+		}
+		boolNode2 := parseBoolNode(&nodeRaw2)
+		assert.Equal(t, boolNode2.Value, false)
+
+		nodeRaw3 = &ant_ast.IdentifierNode{
+			Value: "abcd",
+		}
+		assert.Nil(t, parseBoolNode(&nodeRaw3))
+
+		nodeRaw4 = &ant_ast.BoolNode{
+			Value: true,
+		}
+		assert.Nil(t, parseBoolNode(&nodeRaw4))
+	})
 }