diff --git a/app/api/routers/misc.py b/app/api/routers/misc.py
index d5c4f9f..07a22b9 100644
--- a/app/api/routers/misc.py
+++ b/app/api/routers/misc.py
@@ -294,11 +294,11 @@ def export_issues_csv(project_id: int = None, db: Session = Depends(get_db)):
     issues = query.all()
     output = io.StringIO()
     writer = csv.writer(output)
-    writer.writerow(["id", "title", "type", "status", "priority", "project_id",
+    writer.writerow(["id", "title", "type", "subtype", "status", "priority", "project_id",
                       "reporter_id", "assignee_id", "milestone_id", "due_date",
                       "tags", "created_at", "updated_at"])
     for i in issues:
-        writer.writerow([i.id, i.title, i.issue_type, i.issue_subtype or , i.status, i.priority, i.project_id,
+        writer.writerow([i.id, i.title, i.issue_type, i.issue_subtype or "", i.status, i.priority, i.project_id,
                          i.reporter_id, i.assignee_id, i.milestone_id, i.due_date,
                          i.tags, i.created_at, i.updated_at])
     output.seek(0)
diff --git a/app/models/models.py b/app/models/models.py
index 5cfdace..c7f8315 100644
--- a/app/models/models.py
+++ b/app/models/models.py
@@ -6,16 +6,16 @@ import enum
 
 
 class IssueType(str, enum.Enum):
-    MEETING = meeting
-    SUPPORT = support
-    ISSUE = issue
-    MAINTENANCE = maintenance
-    RESEARCH = research
-    REVIEW = review
-    STORY = story
-    TEST = test
-    RESOLUTION = resolution  # 决议案 - 用于 Agent 僵局提交
-    TASK = task  # legacy generic type
+    MEETING = "meeting"
+    SUPPORT = "support"
+    ISSUE = "issue"
+    MAINTENANCE = "maintenance"
+    RESEARCH = "research"
+    REVIEW = "review"
+    STORY = "story"
+    TEST = "test"
+    RESOLUTION = "resolution"  # 决议案 - 用于 Agent 僵局提交
+    TASK = "task"  # legacy generic type
 
 
 class IssueStatus(str, enum.Enum):
@@ -135,7 +135,7 @@ class ProjectMember(Base):
 
 
 class ProjectCodeCounter(Base):
-    __tablename__ = project_code_counters
+    __tablename__ = "project_code_counters"
 
     id = Column(Integer, primary_key=True, index=True)
     prefix = Column(String(16), unique=True, index=True, nullable=False)