problem using Aggregate functions with joins - asp.net

Question

I have two tables Say Table -A and table-B
Table-A having
Userid | Date
|
101 | 15 Aug ,2011
102 | 15 Aug ,2011
103 | 16 Aug ,2011
104 | 16 Aug ,2011
105 | 17 Aug ,2011
Table -B
Userid(f.k) | sts
101 | x
102 | y
101 | z
103 | x
101 | y
Required output is
Table-C
I want table c output as
DAte ,Total ,Sts as X,Sts as y, Avg of
Date | Total | Sts (if=x) |Sts (if=y) |Avg (Total/2)
15 Aug| 20 | 15 |5 |10
16aug | 30 | 22 |8 |15
I tried using :
select Date, select case when [Tasble-B].Sts='x' Then 0 else 1 END as StsX,select case when [Tasble-B].Sts='Y' Then 0 else 1 END as StsY,Total/2
from
Table-A
inner join Table-B on Table-A.UserID = Table-B.UserID
b group by RegDate
I am getting Error , I am Stuck with this query.Please Help
Thanks in advance

Answer 1

select Date,
select case when [Tasble-B].Sts='x' Then 0
else 1
END as StsX,
select case when [Tasble-B].Sts='Y' Then 0
else 1
END as StsY,
Total/2
from Table-A
inner join Table-B
on Table-A.UserID = Table-B.UserID
b group by RegDate
You do group by RegDate so I assume you should use RegDate in the field list instead of Date or perhaps RegDate as Date.
You are missing the total column. You could do that with count(*) as Total
Your select case ... statements should not be select's but sum(case ...)
Total/2, where does Total come from? My guess is that you want the average of StsX and StsY but it could also mean that you want to use the calculated Total column and divide that by 2. If that is the case you need to repeat your aggregate statement count(*)/2 or you could use this entire query as a sub-query and do the calculation using the field Total as you already do, Total/2.
Your table names need to be encapsulated in brackets [Table-B].
You have an extra b before the group by clause. You should remove that.
`

Answer 2

you can try:
select [Date],
(SUM(case when B.Sts='x' Then 1
else 0
END) +
SUM( case when B.Sts='Y' Then 1
else 0
END)) AS Total,
SUM( case when B.Sts='x' Then 1
else 0
END) AS StsX,
SUM( case when B.Sts='Y' Then 1
else 0
END) as StsY,
(SUM(case when B.Sts='x' Then 1
else 0
END) +
SUM( case when B.Sts='Y' Then 1
else 0
END))
/2.0 AS Average
from A
inner join B
on A.UserID = B.UserID
group by [Date]
I tested it with:
WITH A (UserId, [Date]) AS (
SELECT 101, '2011-08-15'
UNION
SELECT 102, '2011-08-15'
UNION
SELECT 103, '2011-08-16'
UNION
SELECT 104, '2011-08-16'
UNION
SELECT 105, '2011-08-17'
),
B (UserId, sts) AS
(
SELECT 101, 'x'
UNION
SELECT 102, 'y'
UNION
SELECT 101, 'z'
UNION
SELECT 103, 'x'
UNION
SELECT 101, 'y'
)
select [Date],
(SUM(case when B.Sts='x' Then 1
else 0
END) +
SUM( case when B.Sts='Y' Then 1
else 0
END)) AS Total,
SUM( case when B.Sts='x' Then 1
else 0
END) AS StsX,
SUM( case when B.Sts='Y' Then 1
else 0
END) as StsY,
(SUM(case when B.Sts='x' Then 1
else 0
END) +
SUM( case when B.Sts='Y' Then 1
else 0
END))
/2.0 AS Average
from A
inner join B
on A.UserID = B.UserID
group by [Date]