SQL:组合从多个表中选择计数(*)

Question

如何将来自不同表的多个选择计数(*)组合成一个回报？

我和这篇文章有类似的情结

但我想要一次回归.

我尝试了所有的联盟,但它吐了3个不同的计数行.你如何将它们合二为一？

select count(*) from foo1 where ID = '00123244552000258'
union all 
select count(*) from foo2 where ID = '00123244552000258'
union all
select count(*) from foo3 where ID = '00123244552000258'

编辑:我在MS SQL 2005上

Answer 1

SELECT 
(select count(*) from foo1 where ID = '00123244552000258')
+
(select count(*) from foo2 where ID = '00123244552000258')
+
(select count(*) from foo3 where ID = '00123244552000258')

这是一种简单的方法.

Answer 2

select 
  (select count(*) from foo) as foo
, (select count(*) from bar) as bar
, ...

Answer 3

我很惊讶没有人建议这种变化:

SELECT SUM(c)
FROM (
  SELECT COUNT(*) AS c FROM foo1 WHERE ID = '00123244552000258'
  UNION ALL
  SELECT COUNT(*) FROM foo2 WHERE ID = '00123244552000258'
  UNION ALL
  SELECT COUNT(*) FROM foo3 WHERE ID = '00123244552000258'
);

Answer 4

基本上,您将计数作为标准选择中的子查询.

一个例子如下,这将返回1行,两列

SELECT
 (SELECT COUNT(*) FROM MyTable WHERE MyCol = 'MyValue') AS MyTableCount,
 (SELECT COUNT(*) FROM YourTable WHERE MyCol = 'MyValue') AS YourTableCount,