diff --git a/src/app/decks/[deck_id]/InDeck.tsx b/src/app/decks/[deck_id]/InDeck.tsx
index d6a6330..772e730 100644
--- a/src/app/decks/[deck_id]/InDeck.tsx
+++ b/src/app/decks/[deck_id]/InDeck.tsx
@@ -18,6 +18,7 @@ import type { ActionOutputCardWithNote } from "@/modules/card/card-action-dto";
 import type { ActionOutputTodayStudyStats } from "@/modules/card/card-action-dto";
 import type { ActionOutputDeck } from "@/modules/deck/deck-action-dto";
 import { toast } from "sonner";
+import { DEFAULT_NEW_PER_DAY, DEFAULT_REV_PER_DAY } from "@/shared/constant";
 
 
 export function InDeck({ deckId, isReadOnly }: { deckId: number; isReadOnly: boolean; }) {
@@ -29,7 +30,7 @@ export function InDeck({ deckId, isReadOnly }: { deckId: number; isReadOnly: boo
   const [deckInfo, setDeckInfo] = useState<ActionOutputDeck | null>(null);
   const [todayStats, setTodayStats] = useState<ActionOutputTodayStudyStats | null>(null);
   const [openSettingsModal, setSettingsModal] = useState(false);
-  const [settingsForm, setSettingsForm] = useState({ newPerDay: 20, revPerDay: 200 });
+  const [settingsForm, setSettingsForm] = useState({ newPerDay: DEFAULT_NEW_PER_DAY, revPerDay: DEFAULT_REV_PER_DAY });
   const [savingSettings, setSavingSettings] = useState(false);
   const router = useRouter();
   const t = useTranslations("deck_id");
diff --git a/src/modules/card/card-repository.ts b/src/modules/card/card-repository.ts
index ce03706..3043fa1 100644
--- a/src/modules/card/card-repository.ts
+++ b/src/modules/card/card-repository.ts
@@ -346,7 +346,8 @@ export async function repoGetTodayStudyStats(
   startOfToday.setUTCHours(0, 0, 0, 0);
   const todayStart = startOfToday.getTime();
 
-  const revlogs = await prisma.revlog.findMany({
+  const stats = await prisma.revlog.groupBy({
+    by: ["type"],
     where: {
       card: {
         deckId: input.deckId,
@@ -355,30 +356,29 @@ export async function repoGetTodayStudyStats(
         gte: todayStart,
       },
     },
-    select: {
-      id: true,
-      cardId: true,
+    _count: {
       type: true,
     },
   });
 
-  const stats: RepoOutputTodayStudyStats = {
-    newStudied: 0,
-    reviewStudied: 0,
-    learningStudied: 0,
-    totalStudied: 0,
-  };
+  let newStudied = 0;
+  let reviewStudied = 0;
+  let learningStudied = 0;
 
-  for (const revlog of revlogs) {
-    stats.totalStudied++;
-    if (revlog.type === 0) {
-      stats.newStudied++;
-    } else if (revlog.type === 1) {
-      stats.learningStudied++;
-    } else if (revlog.type === 2 || revlog.type === 3) {
-      stats.reviewStudied++;
+  for (const stat of stats) {
+    if (stat.type === 0) {
+      newStudied = stat._count.type;
+    } else if (stat.type === 1) {
+      learningStudied = stat._count.type;
+    } else if (stat.type === 2 || stat.type === 3) {
+      reviewStudied += stat._count.type;
     }
   }
 
-  return stats;
+  return {
+    newStudied,
+    reviewStudied,
+    learningStudied,
+    totalStudied: newStudied + reviewStudied + learningStudied,
+  };
 }
diff --git a/src/shared/constant.ts b/src/shared/constant.ts
index 0915727..c66cf09 100644
--- a/src/shared/constant.ts
+++ b/src/shared/constant.ts
@@ -19,4 +19,18 @@ export const LENGTH_MIN_TRANSLATOR_TEXT = 1;
 export const LENGTH_MAX_USERNAME = 30;
 export const LENGTH_MIN_USERNAME = 3;
 export const LENGTH_MAX_PASSWORD = 100;
-export const LENGTH_MIN_PASSWORD = 8;
\ No newline at end of file
+export const LENGTH_MIN_PASSWORD = 8;
+
+export const FIELD_SEPARATOR = "\x1f";
+
+export const DEFAULT_NEW_PER_DAY = 20;
+export const DEFAULT_REV_PER_DAY = 200;
+
+export const SECONDS_PER_MINUTE = 60;
+export const SECONDS_PER_HOUR = 3600;
+export const SECONDS_PER_DAY = 86400;
+
+export const MS_PER_SECOND = 1000;
+export const MS_PER_MINUTE = 60000;
+export const MS_PER_HOUR = 3600000;
+export const MS_PER_DAY = 86400000;
\ No newline at end of file