select a,b from table where c=1
union all
select 1 as a,2 as b where not exists(select 1 from table where c=1)
select isnull(a,1) as a,isnull(b,2) from table where c=1
可以考虑通过条件属性,在表格中设置一行或者多行默认值,给它们设置条件属性-行高。默认行高为0,逻辑大概就是判断获取数据集的那行值为空的时候,行高就为正常行高