• 当业务表导出时，需要额外添加关联表数据，SQL语句关联查询并拼接比较麻烦
• 框架是通过扩展Database的QueryPageAsync方法的参数来实现

class TestRepository
{
    internal static Task<PagingResult<TbTest>> QueryTestsAsync(Database db, PagingCriteria criteria)
    {
        var sql = "";
        // 导出关联表信息
        List<Test> datas = []; // 查询关联表数据
        if (criteria.ExportMode != ExportMode.None)
        {
            datas = await db.QueryListAsync<Test>(d => d.CompNo == db.User.CompNo);
            // 添加导出附加栏位
            criteria.ExportColumns.Add(new ExportColumnInfo
            {
                Id = "Test",
                Name = "测试",
                IsAdditional = true // 标记为附加栏位
            });
        }

        return db.QueryPageAsync<TbTest>(sql, criteria, (d, c) =>
        {
            if (c.Id == "Test" && d.IsTest) // 判断附加栏位的条件
            {
                var tests = datas?.Where(a => a.HeadId == d.Id);
                return string.Join(Environment.NewLine, tests?.Select(a => a.Name));
            }
            return string.Empty;
        });
    }
}