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数据库查询为空数据问题

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悬赏园豆:80 [已关闭问题] 关闭于 2011-06-22 16:51

select
(select isnull(count(*),0) from RoomContract
where PayModel = '按揭') as '按揭',
(select isnull(count(*),0) from RoomContract
where PayModel = '分期') as '分期',
(select isnull(count(*),0) from RoomContract
where PayModel = '一次性') as '一次性'
from RoomContract

select
 ISNULL(sum(Receivable),0.00) as '学费收入',
 (select ISNULL(sum(Total),0.00) from dbo.BookSellPay
where BookPayName='教材销售缴费' ) as '教材收入',
 (select ISNULL(sum(IncomeMoney),0.00) from dbo.OtherIncome) as '其它收入'
from dbo.PaymentDetails

两条查询语句一样的 但查询出来的结果不一样

第一条

按揭     分期    一次性

没数据的话 就为空   isnull 函数好像没用,但第二条就可以

学费收入      教材收入     其它收入
  0.00           0.00          0.00

怎样让第一条语句和第二条查询出来的结果一样呢

天籁的主页 天籁 | 初学一级 | 园豆:45
提问于:2011-06-16 11:19
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所有回答(6)
0

是不是你过滤条件的字段有为“”,

悍马奔野 | 园豆:212 (菜鸟二级) | 2011-06-16 12:57
0

这个当然是没有结果了,Count统计的是记录个数,如果显示0,那就表示有记录了!

你可以查询(前提是没有记录)

 

Select 0 from RoomContract

 

结果肯定是什么也没有。

邀月 | 园豆:25475 (高人七级) | 2011-06-16 13:51
那应该怎么查?
支持(0) 反对(0) 天籁 | 园豆:45 (初学一级) | 2011-06-16 13:58
0

select
(select isnull(count(*),0) from RoomContract
where PayModel = '按揭') as '按揭',
(select isnull(count(*),0) from RoomContract
where PayModel = '分期') as '分期',
(select isnull(count(*),0) from RoomContract
where PayModel = '一次性') as '一次性'
from RoomContract(你将from roomcontract这句去掉)

直接select
(select count(*) from RoomContract
where PayModel = '按揭') as '按揭',
(select count(*) from RoomContract
where PayModel = '分期') as '分期',
(select count(*) from RoomContract
where PayModel = '一次性') as '一次性'

不知道你是不是想要这个结果

辛巴 | 园豆:622 (小虾三级) | 2011-06-16 14:48
0

select
(select isnull(count(*),0) from RoomContract
where PayModel = '按揭') as '按揭',
(select isnull(count(*),0) from RoomContract
where PayModel = '分期') as '分期',
(select isnull(count(*),0) from RoomContract
where PayModel = '一次性') as '一次性'
from RoomContract

select
ISNULL(sum(Receivable),0.00) as '学费收入',
(select ISNULL(sum(Total),0.00) from dbo.BookSellPay
where BookPayName='教材销售缴费' ) as '教材收入',
(select ISNULL(sum(IncomeMoney),0.00) from dbo.OtherIncome) as '其它收入'
from dbo.PaymentDetails

 

你感觉上下查询一样吗、

宫恒满 | 园豆:210 (菜鸟二级) | 2011-06-16 17:34
就是一个是count 一个是sum 难道用isnull有区别吗
支持(0) 反对(0) 天籁 | 园豆:45 (初学一级) | 2011-06-18 10:33
0

迅捷网络[来送福利] | 园豆:616 (小虾三级) | 2011-06-16 22:12
0

你这个是没有条件的查询,所以会把表里面所有的行都会展现。

第一个SQL是因为RoomContract这个表没有数据,所以显示为空。如果里面有一条数据,则会显示一行三列的0;如果有两条,则有两行三列的0

第二个SQL估计PaymentDetails这个表里面有条数据,而且Receivable是空的。所以会出现第二个情况。

如果要一样结果,则第一个SQL可以查询dual(不知道SQL SERVER是什么表),得到000的结果

Singlou | 园豆:235 (菜鸟二级) | 2011-06-22 15:22
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