简单的 select 问题
我有一个语句 select IsFirst, IsLast from MyTable where pkID = @pkID
（其中IsFirst, IsLast都是bit类型的字段）

我想在搜索不到符合条件的记录时，就伪造一条记录放到查询结果中，比如 返回（ 0， 0 ）这条记录，该如何做？
[解决办法]
select IsFirst, IsLast from MyTable where pkID = @pkID
union all
select 0 IsFirst,0 IsLast from mytable where not exists(select 1 from mytable where pkID = @pkID )
[解决办法]
select IsFirst, IsLast from MyTable where pkID = @pkID
union all
select 0 IsFirst,0 IsLast from (select 1 as n ) a where not exists(select 1 from mytable where pkID = @pkID )
[解决办法]
select isnull(IsFirst,0),isnull( IsLast,0) from MyTable where pkID = @pkID