SELECT COUNT(case when b.Docu_Status='2' then b.Docu_Status else 0 end) AS Expr1,
COUNT(case when b.Docu_Status='5' then b.Docu_Status else 0 end) AS Expr2,
COUNT(case when b.Docu_Status='11' then b.Docu_Status else 0 end) AS Expr3,
COUNT(case when b.Docu_Status='14' then b.Docu_Status else 0 end) AS Expr4
FROM UDP_Project as a INNER JOIN
UDP_Document as b ON a.Project_Id = b.Docu_ForPro
where a.Project_Djsj between '2011-12-27 0:00:00' and '2012-4-16 0:00:00'

SELECT SUM(case when b.Docu_Status='2' then b.Docu_Status else 0 end) AS Expr1,
SUM(case when b.Docu_Status='5' then b.Docu_Status else 0 end) AS Expr2,
SUM(case when b.Docu_Status='11' then b.Docu_Status else 0 end) AS Expr3,
SUM(case when b.Docu_Status='14' then b.Docu_Status else 0 end) AS Expr4
FROM UDP_Project as a INNER JOIN
UDP_Document as b ON a.Project_Id = b.Docu_ForPro
where a.Project_Djsj between '2011-12-27 0:00:00' and '2012-4-16 0:00:00'

------解决方案--------------------
SQL code

SELECT sum(case when b.Docu_Status='2' then 1 else 0 end) AS Expr1,
sum(case when b.Docu_Status='5' then 1 else 0 end) AS Expr2,
sum(case when b.Docu_Status='11' then 1 else 0 end) AS Expr3,
sum(case when b.Docu_Status='14' then 1 else 0 end) AS Expr4
FROM UDP_Project as a INNER JOIN
UDP_Document as b ON a.Project_Id = b.Docu_ForPro
where a.Project_Djsj between '2011-12-27 0:00:00' and '2012-4-16 0:00:00'