要按日期获取GLBalances表的最后一个条目，可以使用OrderByDescending方法按日期降序对GLBalances记录进行排序。
您可以修改查询以实现此目的：

var list = await (from ba in _context.BankAccounts
            join bnk in _context.Banks on ba.BankId equals bnk.ID
            join glB in _context.GLBalances
                .OrderByDescending(glb => glb.Date)
                .Where(glb => glb.GLAccountGuid == ba.BankGL)
                .Take(1) on ba.BankGL equals glB.GLAccountGuid
            select new BankAccountDto()
            {
                BankId = ba.BankId,
                AccountNumber = ba.AccountNumber,
                BankName = bnk.BankName,
                Notes = ba.Notes,
                Description = ba.Description,
                Balance = (decimal)glB.ClosingBalance
            }).ToListAsync();

更新了。试试这个，

var list = await (from ba in _context.BankAccounts
            join bnk in _context.Banks on ba.BankId equals bnk.ID
            join glB in _context.GLBalances.OrderByDescending(glb => glb.EndDate).Take(1)
              on ba.BankGL equals glB.GLAccountGuid 
            where glB.GLAccountGuid == ba.BankGL
            select new BankAccountDto()
            {
                BankId = ba.BankId,
                AccountNumber = ba.AccountNumber,
                BankName = bnk.BankName,
                Notes = ba.Notes,
                Description = ba.Description,
                Balance = (decimal)glB.ClosingBalance
            }).ToListAsync();