Help with SQL - GroupBy and multiple aggregates - tsql

I have a customer table and an orderdetail table
the customer id is a foriegn key in the orderdetail table (I'm simplifying here)
The orderdetail table contains the following columns
OrderId
ItemId
CustomerId
Size
The Size column can take on any one of the following values
1. lr
2. md
3. sm
So the orderdetail table could have the following records (I've comma delimited the columns)
OrderId ItemId CustomerId Size
1,1,30,lr
1,1,30,md
1,1,30,sm
2,1,30,lr
2,1,30,md
3,1,30,lr
3,1,30,sm
4,1,30,lr
5,1,30,md
6,2,30,sm
7,3,30,md
8,3,30,lr
What I'd like is a really efficient query (there's millions of records in the order details tables) that has the following output for a given customerId (30 in this case)
ItemId SizeLr SizeMd SizeSm
1 4 3 2
2 0 0 1
3 1 1 0
The query I'm using uses 3 group by queries (one each for "lr", "md" and "sm") and as a result it scans the table 3 times.
I'm looking for a solution that scans the table just onces. I think the solution is using the new Grouping Set feature in MSSQL 2008. But either ways, a solution using one scan if what I hope someone can help me with.
EDIT
The actual output needs to have other fields from the customer table and the order details table as well. These other fields are not dependent on the aggregates.
For example
ItemName ItemId SizeLr SizeMd SizeSm
A 1 4 3 2
B 2 0 0 1
C 3 1 1 0
Totals 5 4 4
It would nice if I could get the totals for each of the Size columns as well

How about this:
SELECT ItemId,
SUM(CASE WHEN Size = 'Lr' THEN 1 ELSE 0 END) AS SizeLr,
SUM(CASE WHEN Size = 'Md' THEN 1 ELSE 0 END) AS SizeMd,
SUM(CASE WHEN Size = 'Sm' THEN 1 ELSE 0 END) AS SizeSm
FROM OrderDetail
WHERE CustomerId = 30
GROUP BY ItemId

Try this:
select Itemid,
sum (case when Size = 'lr' then 1 else 0 end) SizeLR,
sum (case when Size = 'Md' then 1 else 0 end) SizeMd,
sum (case when Size = 'SM' then 1 else 0 end) SizeSM
from orderdetail
group by Itemid
order by Itemid;
If ItemName is dependent from ItemId you can do this:
select Itemname, Itemid,
sum (case when Size = 'lr' then 1 else 0 end) SizeLR,
sum (case when Size = 'Md' then 1 else 0 end) SizeMd,
sum (case when Size = 'SM' then 1 else 0 end) SizeSM
from orderdetail
group by Itemid, Itemname
order by Itemid;

Related

Postgres: Extracting the IDs and names of people who are cheating the system

I have a table A with the following transaction data:
ID Name Type
1 Albert Rewards
2 Albert Visit
3 Ruddy Rewards
4 Ruddy Visit
5 Ruddy Purchase
6 Mario Rewards
7 Mario Visit
...
I want a table that only select the rows with names of people who used the "Rewards" and "Visit" type but didn't make a purchase, something like this:
ID Name Type
1 Albert Rewards
2 Albert Visit
6 Mario Rewards
7 Mario Visit
...
Any ideas?
The below query will count for every Visit/Rewards/Purchase how often they happened for a given name - and if the respective results are 1/1/0 then all records from the table with that name will be returned.
If fine-tuning is required (such as cases where the count of any of those > 1 etc.) that can be done by fiddling with the numbers in the 'having' clause. The same is true for adding additional categories to check against.
select *
from mytable a
where exists (select b.name,
sum(case when b.type='Rewards' then 1 else 0 end),
sum(case when b.type='Visit' then 1 else 0 end),
sum(case when b.type='Purchase' then 1 else 0 end)
from mytable b
where b.name=a.name
group by b.name
having sum(case when b.type='Rewards' then 1 else 0 end) = 1
and
sum(case when b.type='Visit' then 1 else 0 end) = 1
and
sum(case when b.type='Purchase' then 1 else 0 end) = 0);
For completion sake: SQLFiddle with 2 queries First query also works, but a little differently

combining results of CTEs

I have several CTEs. CTE1A counts number of type A shops in area 1. CTE1B counts number of type B shops in area 1 and so on up to CTE1D. Similarly, CTE2B counts number of type B shops in area 2 and so on. shop_types CTE selects all types of shops: A,B,C,D. How to display a table that shows for each area (column) how many shops of each type there is (rows).
For example:
1 2 3 4 5
A 0 7 4 0 0
B 2 3 8 2 9
C 8 5 8 1 6
D 7 1 5 4 3
Database has 2 tables:
Table regions: shop_id, region_id
Table shops: shop_id, shop_type
WITH
shop_types AS (SELECT DISTINCT shops.shop_type AS type FROM shops WHERE shops.shop_type!='-9999' AND shops.shop_type!='Other'),
cte1A AS (
SELECT regions.region_id, COUNT(regions.shop_id) AS shops_number, shops.shop_type
FROM regions
RIGHT JOIN shops
ON shops.shop_id=regions.shop_id
WHERE regions.region_id=1
AND shops.shop_type='A'
GROUP BY shops.shop_type,regions.region_id)
SELECT * FROM cte1A
I'm not entirely sure I understand why you are after, but it seems you are looking for something like this:
select sh.shop_type,
count(case when r.region_id = 1 then 1 end) as region_1_count,
count(case when r.region_id = 2 then 1 end) as region_2_count,
count(case when r.region_id = 3 then 1 end) as region_3_count
from shops sh
left join regions r on r.shop_id = sh.shop_id
group by sh.shop_type
order by sh.shop_type;
You need to add one case statement for each region you want to have in the output.
If you are using Postgres 9.4 you can replace the case statements using a filter condition which kind of makes the intention a bit easier to understand (I think)
count(*) filter (where r.region_id = 1) as region_1_count,
count(*) filter (where r.region_id = 2) as region_2_count,
...
SQLFiddle: http://sqlfiddle.com/#!1/98391/1
And before you ask: no you can't make the number of columns "dynamic" based on a select statement. The column list for a query must be defined before the statement is actually executed.

how to combine multiple query into one single query

I have three queries as below and I need to combine them into one. Does any body know how to do that?
select COUNT(*) from dbo.VWAnswer where questionId =2 and answer =1
select COUNT(*) from dbo.VWAnswer where questionId =3 and answer =4
select COUNT(*) from dbo.VWAnswer where questionId =5 and answer =2
I want to find out total count of those people whose gender = 1 and Education = 4 and marital status = 2
Following is the table columns(With one ex) that i refer:
questionId questionText anwser AnserSheetID
1 Gender 1 1
2 Qualification 4 1
3 Marital Status 2 1
1 Gender 2 2
2 Qualification 1 2
3 Marital Status 2 2
1 Gender 1 3
2 Qualification 3 3
3 Marital Status 1 3
Basically, these are questions answered by different people whose answers are stored in this table.
So if we consider above table entries I should get 1 as total count based upon above 3 conditions i.e. gender = 1 and Education = 4 and marital status = 2
Can someone tell me what I need to do to get this to work?
If you want to combine your three count queries, you can try the below SQL to get it done.
select
sum(case when questionId =2 and anwser=1 then 1 else 0 end) as FCount,
sum(case when questionId =3 and anwser=4 then 1 else 0 end) as SCount,
sum(case when questionId =5 and anwser=2 then 1 else 0 end) as TCount
from dbo.VWAnswer
Update 1:
select
Sum(case when questionText='Gender' and anwser='1' then 1 else 0 end) as GenderCount,
Sum(case when questionText='Qualification' and anwser='4' then 1 else 0 end) as EducationCount,
Sum(case when questionText='Marital Status' and anwser='2' then 1 else 0 end) as MaritalCount
from VWAnswer
We can only get the counts based on the rows and every condition should apply in each row.
You might use a joined view meeting you conditions and select the count of the rows fitting your conditions.
Select COUNT(*) as cnt from
(
Select a.AnserSheetID
from VWAnswer a
Join VWAnswer b on a.AnserSheetID=b.AnserSheetID and b.questionId = 2 and b.anwser=4
Join VWAnswer c on a.AnserSheetID=c.AnserSheetID and c.questionId = 3 and c.anwser=2
where a.questionId=1 and a.anwser=1
) hlp

Count valid values per user

I have a table with a list of values. -1 is a blank value:
ID FieldType1A FieldType1B FieldType2A FieldType2B Person
1 15 14 10 -1 1
2 16 -1 12 10 1
3 17 -1 5 6 1
4 6 -1 7 -1 2
...
So the result should be:
Person FieldType1 FieldType2
1 4 5
2 1 1
there is a users table with a list of user IDs, would there be a way of iterating over that list of values to generate the person list in the result set (0 for the field types being perfectly valid as it is merely counts)? I think the answer to T-SQL Column Values Count is a step in the direction I'm attempting to go, but unsure how to combine columns that are the same (the A/Bs allow for a list of answers). That and I'm interested in combining all valid values as not attempting to count the number of each valid response.
You can use a CASE expression to change all non-negative-one values to 1, and -1 values to 0, and then sum them up.
SELECT Person,
SUM(CASE WHEN FieldType1A <> -1 THEN 1 ELSE 0 END) +
SUM(CASE WHEN FieldType1B <> -1 THEN 1 ELSE 0 END) AS FieldType1,
SUM(CASE WHEN FieldType2A <> -1 THEN 1 ELSE 0 END) +
SUM(CASE WHEN FieldType2B <> -1 THEN 1 ELSE 0 END) AS FieldType2
FROM YourTable
GROUP BY Person
SELECT Person,
count(nullif(FieldType1A, -1)) + count(nullif(FieldType1B, -1)) as FieldType1,
count(nullif(FieldType2A, -1)) + count(nullif(FieldType2B, -1)) as FieldType2
FROM yourtable
GROUP BY person

Conditional summarizing columns

I have the following situation
ID Value
1 50
1 60
2 70
2 80
1 0
2 50
I need to run a query that would return summed value, grouped by ID. The catch is if the value is 0, then the entire sum should be 0.
Query results would be
ID Value
1 0
2 200
I tried
select ID, case
when Value> 0 then sum(Value) * 1
when Value= 0 then sum(value) * 0
end
from table
but that did not work.
select ID,
sum(value)*sign(min(abs(value))) as [sum(value)]
from YourTable
group by ID
With a case if you like:
select ID,
case sign(min(abs(value)))
when 0 then 0
else sum(value)
end as [sum(value)]
from YourTable
group by ID