如何用sum函数求两个表数据的和

//我要把当前表和历史表的数据相加求出来，我用了以下sql语句，但是发现求不出来。
SELECT count(pk1) as count1 FROM ftrans_info where  user_id='2012050900000001' and tran_code in ('6110','6120','6130')
and tran_date between '2012-01-01' and '2012-05-17' and chk_status = 1 and status = 1
union
SELECT count(pk1) as count2  FROM ftrans_info_hst where   user_id='2012050900000001' and tran_code in ('6110','6120','6130') and tran_date
between '2012-01-01' and '2012-05-17' and chk_status = 1 and status = 1

//以下是上述sql语句的输出结果

COUNT1
23
24

我如何把两个sql语句合并成一个输出，就是我的预想输出是
COUNT1
47 --------------------编程问答-------------------- 再套一层select count(*) from ()不就出来了。 --------------------编程问答-------------------- 是的，发完帖子我就发现自己2了。。。。

select sum(count1) from( SELECT count(pk1) as count1 FROM ftrans_info where user_id='2012050900000001' and tran_code in ('6110','6120','6130')
  and tran_date between '2012-01-01' and '2012-05-17' and chk_status = 1 and status = 1
union
SELECT count(pk1) as count2 FROM ftrans_info_hst where user_id='2012050900000001' and tran_code in ('6110','6120','6130') and tran_date
  between '2012-01-01' and '2012-05-17' and chk_status = 1 and status = 1)
就好了
--------------------编程问答-------------------- declare int @count1,@count2

SELECT @count1 = count(pk1) as count1 FROM ftrans_info where user_id='2012050900000001' and tran_code in ('6110','6120','6130')
and tran_date between '2012-01-01' and '2012-05-17' and chk_status = 1 and status = 1
union
SELECT @count2 = count(pk1) as count2 FROM ftrans_info_hst where user_id='2012050900000001' and tran_code in ('6110','6120','6130') and tran_date
between '2012-01-01' and '2012-05-17' and chk_status = 1 and status = 1

select @count1 + @count2 --------------------编程问答--------------------

引用 3 楼的回复:

declare @count1,@count2 int

SELECT @count1 = count(pk1) as count1 FROM ftrans_info where user_id='2012050900000001' and tran_code in ('6110','6120','6130')
and tran_date between '2012-01-01' and……

刚刚写错了！！
declare @count1 int
declare @count2 int --------------------编程问答-------------------- count 和sum 分清楚了吗？ --------------------编程问答-------------------- 此贴有意思！！程序员也蒙圈啊！！！！ --------------------编程问答-------------------- 偶尔那个脑筋短路呗 --------------------编程问答-------------------- 那就当楼主心好散分吧～～

--------------------编程问答--------------------

补充：Java ,  Java相关