新增“课程统计”模式，展示总体出勤率、状态分布、历次趋势和每位学生的出勤明细。

支持按姓名/学号、行政班及异常情况筛选，默认优先显示低出勤率学生。
新增课程统计 Excel 导出，包含课程概览、学生出勤明细、历次点名趋势三个工作表。
统计仅使用已提交点名；出勤和迟到计为到课，免修不计入应到次数。
修复了枚举兼容问题，已提交点名不会再错误显示为“草稿”，考勤状态中文标签恢复正常。
统计与导出接口均执行教师/数据范围权限校验。

src/Jiaowu.Api/Controllers/AttendanceController.cs

@@ -158,6 +158,9 @@ public sealed class AttendanceController(
             })
             .FirstOrDefaultAsync(cancellationToken);
         if (sheet is null) return NotFound();
+        if (!await AccessibleTasks().AsNoTracking()
+                .AnyAsync(x => x.Id == sheet.TeachingTaskId, cancellationToken))
+            return NotFound();
 
         // Load exemption/deferred in separate query to avoid SQL APPLY (unsupported on SQLite)
         var exemptStudentIds = await db.CourseExemptions
@@ -167,7 +170,10 @@ public sealed class AttendanceController(
             .Where(e => e.TeachingTaskId == sheet.TeachingTaskId && e.Status == ApprovalStatus.Approved)
             .Select(e => e.StudentId).ToHashSetAsync(cancellationToken);
 
-        var canEdit = sheet.Status == AttendanceSheetStatus.Draft;
+        var canEdit = sheet.Status == AttendanceSheetStatus.Draft &&
+                      await CanManageTaskAsync(
+                          sheet.TeachingTaskId,
+                          cancellationToken);
         return Ok(new
         {
             Sheet = new
@@ -277,6 +283,7 @@ public sealed class AttendanceController(
             .Where(x => x.Id == id)
             .Select(x => new
             {
+                x.TeachingTaskId,
                 x.Name,
                 x.AttendanceDate,
                 TaskNumber = x.TeachingTask!.TaskNumber,
@@ -295,6 +302,9 @@ public sealed class AttendanceController(
             })
             .FirstOrDefaultAsync(cancellationToken);
         if (sheetData is null) return NotFound();
+        if (!await AccessibleTasks().AsNoTracking()
+                .AnyAsync(x => x.Id == sheetData.TeachingTaskId, cancellationToken))
+            return NotFound();
 
         var statusLabels = new Dictionary<AttendanceStatus, string>
         {
@@ -316,6 +326,36 @@ public sealed class AttendanceController(
             $"考勤表-{sheetData.TaskNumber}-{sheetData.AttendanceDate:yyyyMMdd}.xlsx");
     }
 
+    [HttpGet("tasks/{teachingTaskId:guid}/statistics")]
+    [Authorize(Roles = AttendanceRoles)]
+    public async Task<ActionResult> GetTaskStatistics(
+        Guid teachingTaskId,
+        CancellationToken cancellationToken)
+    {
+        var statistics = await LoadTaskStatisticsAsync(
+            teachingTaskId,
+            cancellationToken);
+        return statistics is null ? NotFound() : Ok(statistics);
+    }
+
+    [HttpGet("tasks/{teachingTaskId:guid}/statistics.xlsx")]
+    [Authorize(Roles = AttendanceRoles)]
+    public async Task<ActionResult> ExportTaskStatistics(
+        Guid teachingTaskId,
+        CancellationToken cancellationToken)
+    {
+        var statistics = await LoadTaskStatisticsAsync(
+            teachingTaskId,
+            cancellationToken);
+        if (statistics is null) return NotFound();
+
+        var bytes = CreateStatisticsWorkbook(statistics);
+        return File(
+            bytes,
+            ExcelWorkbookHelper.ContentType,
+            $"课程考勤统计-{statistics.Course.TaskNumber}.xlsx");
+    }
+
     [HttpPost("sheets/{id:guid}/submit")]
     [Authorize(Roles = AttendanceRoles)]
     public async Task<ActionResult> Submit(Guid id, CancellationToken cancellationToken)
@@ -592,6 +632,339 @@ public sealed class AttendanceController(
         sheet.TeachingTask!.Teachers.Any(x =>
             x.Teacher?.UserId == currentUserDataScope.Current.UserId);
 
+    private async Task<bool> CanManageTaskAsync(
+        Guid teachingTaskId,
+        CancellationToken cancellationToken)
+    {
+        var scope = currentUserDataScope.Current;
+        if (scope.IsInRole(SystemRoles.SuperAdmin) ||
+            scope.IsInRole(SystemRoles.AcademicAdmin))
+            return true;
+
+        return await db.TeachingTaskTeachers.AsNoTracking()
+            .AnyAsync(
+                x => x.TeachingTaskId == teachingTaskId &&
+                     x.Teacher!.UserId == scope.UserId,
+                cancellationToken);
+    }
+
+    private async Task<AttendanceCourseStatistics?> LoadTaskStatisticsAsync(
+        Guid teachingTaskId,
+        CancellationToken cancellationToken)
+    {
+        var course = await AccessibleTasks().AsNoTracking()
+            .Where(x => x.Id == teachingTaskId)
+            .Select(x => new AttendanceStatisticsCourse(
+                x.Id,
+                x.TaskNumber,
+                x.Name,
+                x.Course!.Code,
+                x.Course.Name,
+                x.AcademicTerm!.Name))
+            .FirstOrDefaultAsync(cancellationToken);
+        if (course is null) return null;
+
+        var enrolledStudents = await db.CourseEnrollments.AsNoTracking()
+            .Where(x =>
+                x.Status == CourseEnrollmentStatus.Enrolled &&
+                x.CourseSelectionOffering!.TeachingTaskId == teachingTaskId)
+            .Select(x => new AttendanceStatisticsStudentIdentity(
+                x.StudentId,
+                x.Student!.StudentNumber,
+                x.Student.Name,
+                x.Student.AdministrativeClass!.Name))
+            .Distinct()
+            .ToListAsync(cancellationToken);
+
+        var submittedSheets = await db.AttendanceSheets.AsNoTracking()
+            .Where(x =>
+                x.TeachingTaskId == teachingTaskId &&
+                x.Status == AttendanceSheetStatus.Submitted)
+            .OrderBy(x => x.AttendanceDate)
+            .ThenBy(x => x.Name)
+            .Select(x => new AttendanceStatisticsSheet(
+                x.Id,
+                x.Name,
+                x.AttendanceDate))
+            .ToListAsync(cancellationToken);
+
+        var records = await db.AttendanceRecords.AsNoTracking()
+            .Where(x =>
+                x.AttendanceSheet!.TeachingTaskId == teachingTaskId &&
+                x.AttendanceSheet.Status == AttendanceSheetStatus.Submitted)
+            .Select(x => new AttendanceStatisticsRecord(
+                x.AttendanceSheetId,
+                x.StudentId,
+                x.Student!.StudentNumber,
+                x.Student.Name,
+                x.Student.AdministrativeClass!.Name,
+                x.Status))
+            .ToListAsync(cancellationToken);
+
+        var identities = enrolledStudents
+            .Concat(records.Select(x => new AttendanceStatisticsStudentIdentity(
+                x.StudentId,
+                x.StudentNumber,
+                x.StudentName,
+                x.ClassName)))
+            .GroupBy(x => x.StudentId)
+            .Select(x => x.First())
+            .ToList();
+
+        var recordsByStudent = records
+            .GroupBy(x => x.StudentId)
+            .ToDictionary(x => x.Key, x => x.ToList());
+        var students = identities.Select(identity =>
+        {
+            var studentRecords = recordsByStudent.GetValueOrDefault(identity.StudentId) ?? [];
+            var present = studentRecords.Count(x => x.Status == AttendanceStatus.Present);
+            var absent = studentRecords.Count(x => x.Status == AttendanceStatus.Absent);
+            var late = studentRecords.Count(x => x.Status == AttendanceStatus.Late);
+            var leave = studentRecords.Count(x => x.Status == AttendanceStatus.Leave);
+            var excused = studentRecords.Count(x => x.Status == AttendanceStatus.Excused);
+            var required = studentRecords.Count - excused;
+            return new AttendanceStudentStatistics(
+                identity.StudentId,
+                identity.StudentNumber,
+                identity.StudentName,
+                identity.ClassName,
+                studentRecords.Count,
+                required,
+                present,
+                absent,
+                late,
+                leave,
+                excused,
+                CalculateAttendanceRate(present, late, required));
+        })
+        .OrderBy(x => x.AttendanceRate ?? decimal.MaxValue)
+        .ThenBy(x => x.StudentNumber)
+        .ToList();
+
+        var recordsBySheet = records
+            .GroupBy(x => x.AttendanceSheetId)
+            .ToDictionary(x => x.Key, x => x.ToList());
+        var sessions = submittedSheets.Select(sheet =>
+        {
+            var sheetRecords = recordsBySheet.GetValueOrDefault(sheet.Id) ?? [];
+            var present = sheetRecords.Count(x => x.Status == AttendanceStatus.Present);
+            var absent = sheetRecords.Count(x => x.Status == AttendanceStatus.Absent);
+            var late = sheetRecords.Count(x => x.Status == AttendanceStatus.Late);
+            var leave = sheetRecords.Count(x => x.Status == AttendanceStatus.Leave);
+            var excused = sheetRecords.Count(x => x.Status == AttendanceStatus.Excused);
+            var required = sheetRecords.Count - excused;
+            return new AttendanceSessionStatistics(
+                sheet.Id,
+                sheet.Name,
+                sheet.AttendanceDate,
+                sheetRecords.Count,
+                required,
+                present,
+                absent,
+                late,
+                leave,
+                excused,
+                CalculateAttendanceRate(present, late, required));
+        }).ToList();
+
+        var totalPresent = records.Count(x => x.Status == AttendanceStatus.Present);
+        var totalAbsent = records.Count(x => x.Status == AttendanceStatus.Absent);
+        var totalLate = records.Count(x => x.Status == AttendanceStatus.Late);
+        var totalLeave = records.Count(x => x.Status == AttendanceStatus.Leave);
+        var totalExcused = records.Count(x => x.Status == AttendanceStatus.Excused);
+        var totalRequired = records.Count - totalExcused;
+        var summary = new AttendanceStatisticsSummary(
+            students.Count,
+            sessions.Count,
+            records.Count,
+            totalRequired,
+            CalculateAttendanceRate(totalPresent, totalLate, totalRequired),
+            students.Count(x =>
+                x.RequiredCount > 0 &&
+                x.PresentCount == x.RequiredCount),
+            students.Count(x => x.AbsentCount > 0 || x.LateCount > 0));
+        var distribution = new[]
+        {
+            new AttendanceStatusStatistics(
+                AttendanceStatus.Present,
+                "出勤",
+                totalPresent),
+            new AttendanceStatusStatistics(
+                AttendanceStatus.Absent,
+                "缺勤",
+                totalAbsent),
+            new AttendanceStatusStatistics(
+                AttendanceStatus.Late,
+                "迟到",
+                totalLate),
+            new AttendanceStatusStatistics(
+                AttendanceStatus.Leave,
+                "请假",
+                totalLeave),
+            new AttendanceStatusStatistics(
+                AttendanceStatus.Excused,
+                "免修",
+                totalExcused)
+        };
+
+        return new AttendanceCourseStatistics(
+            course,
+            summary,
+            distribution,
+            sessions,
+            students);
+    }
+
+    private static decimal? CalculateAttendanceRate(
+        int present,
+        int late,
+        int required)
+    {
+        if (required <= 0) return null;
+        return Math.Round(
+            (present + late) * 100m / required,
+            1,
+            MidpointRounding.AwayFromZero);
+    }
+
+    private static byte[] CreateStatisticsWorkbook(
+        AttendanceCourseStatistics statistics)
+    {
+        using var workbook = new XLWorkbook();
+        var overview = workbook.Worksheets.Add("课程概览");
+        overview.Cell("A1").Value = "课程考勤统计";
+        overview.Cell("A1").Style.Font.Bold = true;
+        overview.Cell("A1").Style.Font.FontSize = 16;
+        overview.Cell("A1").Style.Font.FontColor = XLColor.FromHtml("#1F3A6D");
+        var overviewRows = new (string Label, object? Value)[]
+        {
+            ("课程", $"{statistics.Course.CourseCode} {statistics.Course.CourseName}"),
+            ("教学任务", statistics.Course.TaskNumber),
+            ("学期", statistics.Course.TermName),
+            ("学生人数", statistics.Summary.StudentCount),
+            ("已提交点名", statistics.Summary.SubmittedSheetCount),
+            ("考勤记录", statistics.Summary.RecordCount),
+            ("课程总体出勤率", statistics.Summary.OverallAttendanceRate),
+            ("全勤人数", statistics.Summary.PerfectAttendanceCount),
+            ("存在缺勤或迟到人数", statistics.Summary.AbnormalStudentCount),
+            ("统计口径", "仅统计已提交点名；出勤和迟到计为到课，免修不计入应到次数。")
+        };
+        for (var index = 0; index < overviewRows.Length; index++)
+        {
+            var row = index + 3;
+            overview.Cell(row, 1).Value = overviewRows[index].Label;
+            overview.Cell(row, 1).Style.Font.Bold = true;
+            if (overviewRows[index].Value is decimal rate)
+            {
+                overview.Cell(row, 2).Value = rate / 100m;
+                overview.Cell(row, 2).Style.NumberFormat.Format = "0.0%";
+            }
+            else
+            {
+                overview.Cell(row, 2).Value =
+                    overviewRows[index].Value?.ToString() ?? "暂无";
+            }
+        }
+        overview.Column(1).Width = 22;
+        overview.Column(2).Width = 58;
+        overview.Style.Alignment.Vertical = XLAlignmentVerticalValues.Center;
+
+        var studentSheet = workbook.Worksheets.Add("学生出勤明细");
+        var studentHeaders = new[]
+        {
+            "学号", "姓名", "行政班", "统计次数", "应到次数",
+            "出勤", "缺勤", "迟到", "请假", "免修", "出勤率"
+        };
+        WriteHeader(studentSheet, studentHeaders);
+        for (var index = 0; index < statistics.Students.Count; index++)
+        {
+            var student = statistics.Students[index];
+            var row = index + 2;
+            studentSheet.Cell(row, 1).Value = student.StudentNumber;
+            studentSheet.Cell(row, 2).Value = student.StudentName;
+            studentSheet.Cell(row, 3).Value = student.ClassName;
+            studentSheet.Cell(row, 4).Value = student.TotalCount;
+            studentSheet.Cell(row, 5).Value = student.RequiredCount;
+            studentSheet.Cell(row, 6).Value = student.PresentCount;
+            studentSheet.Cell(row, 7).Value = student.AbsentCount;
+            studentSheet.Cell(row, 8).Value = student.LateCount;
+            studentSheet.Cell(row, 9).Value = student.LeaveCount;
+            studentSheet.Cell(row, 10).Value = student.ExcusedCount;
+            if (student.AttendanceRate.HasValue)
+            {
+                studentSheet.Cell(row, 11).Value =
+                    student.AttendanceRate.Value / 100m;
+                studentSheet.Cell(row, 11).Style.NumberFormat.Format = "0.0%";
+            }
+            else
+            {
+                studentSheet.Cell(row, 11).Value = "暂无";
+            }
+        }
+        FinishDataSheet(studentSheet, studentHeaders.Length);
+
+        var sessionSheet = workbook.Worksheets.Add("历次点名趋势");
+        var sessionHeaders = new[]
+        {
+            "日期", "点名名称", "记录数", "应到人数",
+            "出勤", "缺勤", "迟到", "请假", "免修", "出勤率"
+        };
+        WriteHeader(sessionSheet, sessionHeaders);
+        for (var index = 0; index < statistics.Sessions.Count; index++)
+        {
+            var session = statistics.Sessions[index];
+            var row = index + 2;
+            sessionSheet.Cell(row, 1).Value = session.AttendanceDate;
+            sessionSheet.Cell(row, 1).Style.DateFormat.Format = "yyyy-mm-dd";
+            sessionSheet.Cell(row, 2).Value = session.Name;
+            sessionSheet.Cell(row, 3).Value = session.TotalCount;
+            sessionSheet.Cell(row, 4).Value = session.RequiredCount;
+            sessionSheet.Cell(row, 5).Value = session.PresentCount;
+            sessionSheet.Cell(row, 6).Value = session.AbsentCount;
+            sessionSheet.Cell(row, 7).Value = session.LateCount;
+            sessionSheet.Cell(row, 8).Value = session.LeaveCount;
+            sessionSheet.Cell(row, 9).Value = session.ExcusedCount;
+            if (session.AttendanceRate.HasValue)
+            {
+                sessionSheet.Cell(row, 10).Value =
+                    session.AttendanceRate.Value / 100m;
+                sessionSheet.Cell(row, 10).Style.NumberFormat.Format = "0.0%";
+            }
+            else
+            {
+                sessionSheet.Cell(row, 10).Value = "暂无";
+            }
+        }
+        FinishDataSheet(sessionSheet, sessionHeaders.Length);
+
+        using var stream = new MemoryStream();
+        workbook.SaveAs(stream);
+        return stream.ToArray();
+    }
+
+    private static void WriteHeader(
+        IXLWorksheet sheet,
+        IReadOnlyList<string> headers)
+    {
+        for (var index = 0; index < headers.Count; index++)
+        {
+            var cell = sheet.Cell(1, index + 1);
+            cell.Value = headers[index];
+            cell.Style.Font.Bold = true;
+            cell.Style.Font.FontColor = XLColor.White;
+            cell.Style.Fill.BackgroundColor = XLColor.FromHtml("#1F3A6D");
+            cell.Style.Alignment.Horizontal = XLAlignmentHorizontalValues.Center;
+        }
+    }
+
+    private static void FinishDataSheet(IXLWorksheet sheet, int columnCount)
+    {
+        sheet.SheetView.FreezeRows(1);
+        sheet.RangeUsed()?.SetAutoFilter();
+        sheet.Columns(1, columnCount).AdjustToContents(10, 28);
+        sheet.Style.Alignment.Vertical = XLAlignmentVerticalValues.Center;
+    }
+
     private static string? Normalize(string? value) =>
         string.IsNullOrWhiteSpace(value) ? null : value.Trim();
 
@@ -625,3 +998,78 @@ public sealed record AttendanceAppealRequest(
 public sealed record AttendanceAppealReviewRequest(
     bool Approve,
     [MaxLength(300)] string? Comment);
+
+public sealed record AttendanceCourseStatistics(
+    AttendanceStatisticsCourse Course,
+    AttendanceStatisticsSummary Summary,
+    IReadOnlyList<AttendanceStatusStatistics> StatusDistribution,
+    IReadOnlyList<AttendanceSessionStatistics> Sessions,
+    IReadOnlyList<AttendanceStudentStatistics> Students);
+
+public sealed record AttendanceStatisticsCourse(
+    Guid Id,
+    string TaskNumber,
+    string TaskName,
+    string CourseCode,
+    string CourseName,
+    string TermName);
+
+public sealed record AttendanceStatisticsSummary(
+    int StudentCount,
+    int SubmittedSheetCount,
+    int RecordCount,
+    int RequiredCount,
+    decimal? OverallAttendanceRate,
+    int PerfectAttendanceCount,
+    int AbnormalStudentCount);
+
+public sealed record AttendanceStatusStatistics(
+    AttendanceStatus Status,
+    string Label,
+    int Count);
+
+public sealed record AttendanceSessionStatistics(
+    Guid Id,
+    string Name,
+    DateTime AttendanceDate,
+    int TotalCount,
+    int RequiredCount,
+    int PresentCount,
+    int AbsentCount,
+    int LateCount,
+    int LeaveCount,
+    int ExcusedCount,
+    decimal? AttendanceRate);
+
+public sealed record AttendanceStudentStatistics(
+    Guid StudentId,
+    string StudentNumber,
+    string StudentName,
+    string ClassName,
+    int TotalCount,
+    int RequiredCount,
+    int PresentCount,
+    int AbsentCount,
+    int LateCount,
+    int LeaveCount,
+    int ExcusedCount,
+    decimal? AttendanceRate);
+
+internal sealed record AttendanceStatisticsStudentIdentity(
+    Guid StudentId,
+    string StudentNumber,
+    string StudentName,
+    string ClassName);
+
+internal sealed record AttendanceStatisticsSheet(
+    Guid Id,
+    string Name,
+    DateTime AttendanceDate);
+
+internal sealed record AttendanceStatisticsRecord(
+    Guid AttendanceSheetId,
+    Guid StudentId,
+    string StudentNumber,
+    string StudentName,
+    string ClassName,
+    AttendanceStatus Status);

tests/Jiaowu.Api.Tests/AttendanceControllerTests.cs

@@ -0,0 +1,195 @@
+using ClosedXML.Excel;
+using Jiaowu.Api.Controllers;
+using Jiaowu.Api.Domain.Academic;
+using Jiaowu.Api.Domain.Identity;
+using Jiaowu.Api.Infrastructure.Auth;
+using Jiaowu.Api.Infrastructure.Persistence;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Data.Sqlite;
+using Microsoft.EntityFrameworkCore;
+
+namespace Jiaowu.Api.Tests;
+
+public sealed class AttendanceControllerTests
+{
+    [Fact]
+    public async Task TaskStatistics_UsesSubmittedSheetsAndExportsAllDetails()
+    {
+        await using var connection = new SqliteConnection("Data Source=:memory:");
+        await connection.OpenAsync();
+        var options = new DbContextOptionsBuilder<AppDbContext>()
+            .UseSqlite(connection)
+            .Options;
+        await using var db = new AppDbContext(options);
+        await db.Database.EnsureCreatedAsync();
+
+        var college = new College { Code = "CS", Name = "计算机学院" };
+        var major = new Major
+        {
+            Code = "080901",
+            Name = "计算机科学与技术",
+            CollegeId = college.Id,
+            DegreeType = "工学学士"
+        };
+        var administrativeClass = new AdministrativeClass
+        {
+            Code = "CS2026-01",
+            Name = "计科 2026-1 班",
+            MajorId = major.Id,
+            Grade = 2026
+        };
+        var firstStudent = new Student
+        {
+            StudentNumber = "202601001",
+            Name = "周同学",
+            AdministrativeClassId = administrativeClass.Id,
+            EnrollmentYear = 2026,
+            EnrollmentDate = new DateOnly(2026, 9, 1)
+        };
+        var secondStudent = new Student
+        {
+            StudentNumber = "202601002",
+            Name = "吴同学",
+            AdministrativeClassId = administrativeClass.Id,
+            EnrollmentYear = 2026,
+            EnrollmentDate = new DateOnly(2026, 9, 1)
+        };
+        var course = new Course
+        {
+            Code = "CS101",
+            Name = "程序设计基础",
+            CollegeId = college.Id,
+            Credits = 4,
+            TotalHours = 64,
+            LectureHours = 48,
+            PracticeHours = 16,
+            Nature = CourseNature.MajorRequired,
+            AssessmentMethod = AssessmentMethod.Examination
+        };
+        var term = new AcademicTerm
+        {
+            Code = "2026-1",
+            Name = "2026—2027 学年第一学期",
+            AcademicYear = "2026-2027",
+            Season = TermSeason.Autumn,
+            StartDate = new DateOnly(2026, 9, 1),
+            EndDate = new DateOnly(2027, 1, 20)
+        };
+        var task = new TeachingTask
+        {
+            TaskNumber = "2026-1-CS101-01",
+            Name = "程序设计基础教学班",
+            AcademicTermId = term.Id,
+            CourseId = course.Id,
+            Capacity = 60,
+            Status = TeachingTaskStatus.Published
+        };
+        db.AddRange(
+            college,
+            major,
+            administrativeClass,
+            firstStudent,
+            secondStudent,
+            course,
+            term,
+            task);
+        await db.SaveChangesAsync();
+
+        db.AttendanceSheets.AddRange(
+            new AttendanceSheet
+            {
+                TeachingTaskId = task.Id,
+                Name = "第1周点名",
+                AttendanceDate = new DateTime(2026, 9, 3),
+                Status = AttendanceSheetStatus.Submitted,
+                Records =
+                [
+                    new AttendanceRecord
+                    {
+                        StudentId = firstStudent.Id,
+                        Status = AttendanceStatus.Present
+                    },
+                    new AttendanceRecord
+                    {
+                        StudentId = secondStudent.Id,
+                        Status = AttendanceStatus.Absent
+                    }
+                ]
+            },
+            new AttendanceSheet
+            {
+                TeachingTaskId = task.Id,
+                Name = "第2周点名",
+                AttendanceDate = new DateTime(2026, 9, 10),
+                Status = AttendanceSheetStatus.Submitted,
+                Records =
+                [
+                    new AttendanceRecord
+                    {
+                        StudentId = firstStudent.Id,
+                        Status = AttendanceStatus.Late
+                    },
+                    new AttendanceRecord
+                    {
+                        StudentId = secondStudent.Id,
+                        Status = AttendanceStatus.Excused
+                    }
+                ]
+            },
+            new AttendanceSheet
+            {
+                TeachingTaskId = task.Id,
+                Name = "未提交点名",
+                AttendanceDate = new DateTime(2026, 9, 17),
+                Status = AttendanceSheetStatus.Draft,
+                Records =
+                [
+                    new AttendanceRecord
+                    {
+                        StudentId = firstStudent.Id,
+                        Status = AttendanceStatus.Absent
+                    }
+                ]
+            });
+        await db.SaveChangesAsync();
+
+        var controller = new AttendanceController(db, new AllDataScope());
+        var result = await controller.GetTaskStatistics(
+            task.Id,
+            CancellationToken.None);
+
+        var ok = Assert.IsType<OkObjectResult>(result);
+        var statistics = Assert.IsType<AttendanceCourseStatistics>(ok.Value);
+        Assert.Equal(2, statistics.Summary.SubmittedSheetCount);
+        Assert.Equal(4, statistics.Summary.RecordCount);
+        Assert.Equal(3, statistics.Summary.RequiredCount);
+        Assert.Equal(66.7m, statistics.Summary.OverallAttendanceRate);
+        Assert.Equal(0, statistics.Summary.PerfectAttendanceCount);
+        Assert.Equal(2, statistics.Students.Count);
+        Assert.Equal(0m, statistics.Students[0].AttendanceRate);
+        Assert.Equal(100m, statistics.Students[1].AttendanceRate);
+
+        var exportResult = await controller.ExportTaskStatistics(
+            task.Id,
+            CancellationToken.None);
+        var file = Assert.IsType<FileContentResult>(exportResult);
+        using var workbook = new XLWorkbook(new MemoryStream(file.FileContents));
+        Assert.NotNull(workbook.Worksheet("课程概览"));
+        Assert.Equal(
+            3,
+            workbook.Worksheet("学生出勤明细").LastRowUsed()!.RowNumber());
+        Assert.Equal(
+            3,
+            workbook.Worksheet("历次点名趋势").LastRowUsed()!.RowNumber());
+    }
+
+    private sealed class AllDataScope : ICurrentUserDataScope
+    {
+        public CurrentUserScope Current { get; } = new(
+            Guid.NewGuid(),
+            "测试管理员",
+            null,
+            DataScope.All,
+            new HashSet<string>([SystemRoles.SuperAdmin]));
+    }
+}