diff --git a/pkg/api/transactions.go b/pkg/api/transactions.go
index 2efc26df..174fdce8 100644
--- a/pkg/api/transactions.go
+++ b/pkg/api/transactions.go
@@ -43,23 +43,11 @@ func (a *TransactionsApi) TransactionCountHandler(c *core.Context) (interface{},
 
 	uid := c.GetCurrentUid()
 
-	var allCategoryIds []int64
+	allCategoryIds, err := a.getCategoryAndSubCategoryIds(transactionCountReq.CategoryId, uid)
 
-	if transactionCountReq.CategoryId > 0 {
-		allSubCategories, err := a.transactionCategories.GetAllCategoriesByUid(uid, 0, transactionCountReq.CategoryId)
-
-		if err != nil {
-			log.WarnfWithRequestId(c, "[transactions.TransactionCountHandler] get transaction category error, because %s", err.Error())
-			return nil, errs.ErrOperationFailed
-		}
-
-		if len(allSubCategories) > 0 {
-			for i := 0; i < len(allSubCategories); i++ {
-				allCategoryIds = append(allCategoryIds, allSubCategories[i].CategoryId)
-			}
-		} else {
-			allCategoryIds = append(allCategoryIds, transactionCountReq.CategoryId)
-		}
+	if err != nil {
+		log.WarnfWithRequestId(c, "[transactions.TransactionCountHandler] get transaction category error, because %s", err.Error())
+		return nil, errs.ErrOperationFailed
 	}
 
 	totalCount, err := a.transactions.GetTransactionCount(uid, transactionCountReq.MaxTime, transactionCountReq.MinTime, transactionCountReq.Type, allCategoryIds, transactionCountReq.AccountId, transactionCountReq.Keyword)
@@ -99,23 +87,11 @@ func (a *TransactionsApi) TransactionListHandler(c *core.Context) (interface{},
 		return nil, errs.ErrUserNotFound
 	}
 
-	var allCategoryIds []int64
+	allCategoryIds, err := a.getCategoryAndSubCategoryIds(transactionListReq.CategoryId, uid)
 
-	if transactionListReq.CategoryId > 0 {
-		allSubCategories, err := a.transactionCategories.GetAllCategoriesByUid(uid, 0, transactionListReq.CategoryId)
-
-		if err != nil {
-			log.WarnfWithRequestId(c, "[transactions.TransactionListHandler] get transaction category error, because %s", err.Error())
-			return nil, errs.ErrOperationFailed
-		}
-
-		if len(allSubCategories) > 0 {
-			for i := 0; i < len(allSubCategories); i++ {
-				allCategoryIds = append(allCategoryIds, allSubCategories[i].CategoryId)
-			}
-		} else {
-			allCategoryIds = append(allCategoryIds, transactionListReq.CategoryId)
-		}
+	if err != nil {
+		log.WarnfWithRequestId(c, "[transactions.TransactionListHandler] get transaction category error, because %s", err.Error())
+		return nil, errs.ErrOperationFailed
 	}
 
 	transactions, err := a.transactions.GetTransactionsByMaxTime(uid, transactionListReq.MaxTime, transactionListReq.MinTime, transactionListReq.Type, allCategoryIds, transactionListReq.AccountId, transactionListReq.Keyword, transactionListReq.Count+1, true)
@@ -264,23 +240,11 @@ func (a *TransactionsApi) TransactionMonthListHandler(c *core.Context) (interfac
 		return nil, errs.ErrUserNotFound
 	}
 
-	var allCategoryIds []int64
+	allCategoryIds, err := a.getCategoryAndSubCategoryIds(transactionListReq.CategoryId, uid)
 
-	if transactionListReq.CategoryId > 0 {
-		allSubCategories, err := a.transactionCategories.GetAllCategoriesByUid(uid, 0, transactionListReq.CategoryId)
-
-		if err != nil {
-			log.WarnfWithRequestId(c, "[transactions.TransactionMonthListHandler] get transaction category error, because %s", err.Error())
-			return nil, errs.ErrOperationFailed
-		}
-
-		if len(allSubCategories) > 0 {
-			for i := 0; i < len(allSubCategories); i++ {
-				allCategoryIds = append(allCategoryIds, allSubCategories[i].CategoryId)
-			}
-		} else {
-			allCategoryIds = append(allCategoryIds, transactionListReq.CategoryId)
-		}
+	if err != nil {
+		log.WarnfWithRequestId(c, "[transactions.TransactionMonthListHandler] get transaction category error, because %s", err.Error())
+		return nil, errs.ErrOperationFailed
 	}
 
 	transactions, err := a.transactions.GetTransactionsInMonthByPage(uid, transactionListReq.Year, transactionListReq.Month, transactionListReq.Type, allCategoryIds, transactionListReq.AccountId, transactionListReq.Keyword, transactionListReq.Page, transactionListReq.Count, utcOffset)
@@ -765,6 +729,28 @@ func (a *TransactionsApi) filterTransactions(c *core.Context, uid int64, transac
 	return finalTransactions
 }
 
+func (a *TransactionsApi) getCategoryAndSubCategoryIds(categoryId int64, uid int64) ([]int64, error) {
+	var allCategoryIds []int64
+
+	if categoryId > 0 {
+		allSubCategories, err := a.transactionCategories.GetAllCategoriesByUid(uid, 0, categoryId)
+
+		if err != nil {
+			return nil, err
+		}
+
+		if len(allSubCategories) > 0 {
+			for i := 0; i < len(allSubCategories); i++ {
+				allCategoryIds = append(allCategoryIds, allSubCategories[i].CategoryId)
+			}
+		} else {
+			allCategoryIds = append(allCategoryIds, categoryId)
+		}
+	}
+
+	return allCategoryIds, nil
+}
+
 func (a *TransactionsApi) getTransactionTagIds(allTransactionTagIds map[int64][]int64) []int64 {
 	allTagIds := make([]int64, 0, len(allTransactionTagIds))