你的事sqlserver数据库?试试这样
b.Totals.AddExp("合同已签","case when 合同已签 = true then 1 else 0 end","合同已签数量")
或者
b.Totals.AddExp("合同已签","case when 合同已签 = 1 then 1 else 0 end","合同已签数量")