SQL 两个表格交互，字符串合并，并且摒除相同的字符串

ERP软件做表格是碰到一部分问题，记下来。

主要是将两个表格并在一起，并且把多行转成一行。

表1-task: taskid,customer,engineering

表2-yieldinfo:yieldid, taskid ,product,yield_num,price,money，yieldtime 　　////每个yieldid对应的product列只有一个值

做成查询某一时间段内的：customer，engineering，product，price，money，yield_num,其中product为多行转一行。

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product的多行转一行函数：

ALTER FUNCTION [dbo].[f_str_pro](@cus varchar(200),@eng varchar(200),@starttime varchar(30),@endtime varchar(30))
RETURNS varchar(2000)
AS
BEGIN    
  DECLARE @r varchar(2000)
  SET @r = ‘‘
  SELECT @r=@r + ‘,‘ + a.product      ////多行转一行     
  FROM (select distinct t.customer,t.engineering,y.product
    from yieldinfo y left join task t on t.taskid=y.taskid left join department d on d.depid=y.depid
    where y.audit=1 and y.yield_time>=@starttime and y.yield_time<@endtime)a
    where  a.customer=@cus and a.engineering=@eng
RETURN STUFF(@r, 1, 1, ‘‘)
end

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被除数为0时，返回0.

isnull(((sum(a.money))/(nullif ((sum(a.yield_num)),0))),0)

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SQL查询语句：

 select a.customer,a.engineering,sum(a.yield_num)as yield_num, round(isnull(((sum(a.money))/(nullif ((sum(a.yield_num)),0))),0),0)as price,
 (dbo.f_str_pro(a.customer,a.engineering,‘2013-08-20 11:06:44‘,‘2014-01-20 11:06:44‘)) as product, sum(a.money)as money
 from (select t.customer,t.engineering,sum(y.yield_num)as yield_num,
 round(isnull(((sum(y.money))/(nullif ((sum(y.yield_num)),0))),0),0)as price,
 t.product,sum(y.money)as money
  from yieldinfo y left join task t on t.taskid=y.taskid
  where y.audit=1 and y.yield_time>=‘2013-08-20 11:06:44‘ and y.yield_time<‘2014-01-20 11:06:44‘
   group by t.product,engineering,customer)a
   group by a.engineering,a.customer
   order by customer