Doing a Sum() on a column adds up the values in that column based on group by. But lets say I want to sum these values only if all the values are not null or not 0, then I need a clause which checks if any of the values is 0 before it does the sum. How can I implement such a clause?
I'm using sql server 2005.
Thanks,
Barry
Let's supose your table schema is:
myTable( id, colA, value)
Then, one approach is:
Select colA, sum(value)
from myTable
group by colA
having count( id ) = count( nullif( value, 0 ))
Notice that nullif is a MSSQL server function. YOu should adapt code to your rdbms brand.
Explanation:
count aggregate function only count not null values. Here a counting null values test.
You say that 0+2+3=0 for this case. Assuming that NULL+2+3 should also be zero:
SELECT GroupField,
SUM(Value) * MIN(CASE WHEN COALESCE(Value, 0) = 0 THEN 0 ELSE 1 END)
FROM SumNonZero
GROUP BY GroupField
The above statement gives this result
GroupField (No column name)
case1 5
case2 0
case3 0
with this test data
CREATE TABLE SumNonZero (
GroupField CHAR(5) NOT NULL,
Value INT
)
INSERT INTO SumNonZero(GroupField, Value)
SELECT 'case1', 2
UNION ALL SELECT 'case1', 3
UNION ALL SELECT 'case2', 0
UNION ALL SELECT 'case2', 2
UNION ALL SELECT 'case2', 3
UNION ALL SELECT 'case3', NULL
UNION ALL SELECT 'case3', 3
UNION ALL SELECT 'case3', 4
It makes no sense to eliminate 0 from a SUM because it wont impact the sum.
But you may want to SUM based on another field:
select FIELD, sum(
case when(OTHER_FIELD>0) then FIELD
else 0
end)
from TABLE
group by TABLE
Related
I am trying to create a column in SQL SERVER that shows 1 OR 0(zero). I have a column of customer numbers that appear more than once. At the first hit on a unique non-repeated customer number it should show one and if it is repeated then 0(zero). How can I create this ?
CustNumber Unique
25122134 1
25122134 0
25122134 0
25122136 1
25122136 0
the solutions I am considering and trying out now are Rank() and Rank_DENSE().
declare #test table
(
CustNumber int
)
insert into #test values
(25122134),
(25122134),
(25122134),
(25122136),
(25122136)
select
* ,
// each CustNumber in partition has the same rank, but different row_number
case when (row_number() over (partition by CustNumber order by CustNumber)) = 1
then 1 else 0 end as [Unique]
// the 1st is unique, the rest (2..n) are not
from #test
order by CustNumber, [Unique] desc
// unique in each group should be displayed first
You don't want RANK because that, by definition, produces the same output for identical inputs.
ROW_NUMBER() and a simple CASE expression should do it:
;WITH Numbered as (
SELECT CustNumber,
ROW_NUMBER() OVER (PARTITION BY CustNumber
ORDER BY CustNumber) as rn --Unusual - pick a real column if you have a preference
FROM YourUnnamedTable
)
SELECT CustNumber,CASE WHEN rn = 1 THEN 1 ELSE 0 END as [Unique]
FROM Numbered
What could be wrong with this query:
SELECT
SUM(CASE
WHEN (SELECT TOP 1 ISNULL(StartDate,'01-01-1900')
FROM TestingTable
ORDER BY StartDate Asc) <> '01-01-1900' THEN 1 ELSE 0 END) AS Testingvalue.
The get the error:
Cannot perform an aggregate function on an expression containing an aggregate or a subquery.
As koppinjo stated what your current (broken) query is doing is checking if you have a NULL-value (or StartDate = '01-01-1900') in your table, return either a 1 or a 0 depending on which, and then attempting to SUM that single value.
There are 2 different logical things you want.
Either getting the amount of rows that has a StartDate or checking if any row is missing StartDate.
SELECT --Checking if there is a NULL-value in table
(
CASE WHEN
(SELECT TOP 1 ISNULL(StartDate,'01-01-1900')
FROM TestingTable
ORDER BY StartDate Asc) <> '01-01-1900' THEN 1
ELSE 0
END
) AS TestingValue
SELECT SUM(TestingValue) TestingValue --Give the count of how many non-NULLs there is
FROM
(
SELECT
CASE WHEN
ISNULL(StartDate,'01-01-1900') <> '01-01-1900' THEN 1
ELSE 0
END AS TestingValue
FROM TestingTable
) T
Here is a SQL Fiddle showing both outputs side by side.
Hard to say, but you probably want something like this:
SELECT
SUM(TestingValue)
FROM
(SELECT
CASE
WHEN ISNULL(StartDate,'01-01-1900') <> '01-01-1900'
THEN 1
ELSE 0
END AS TestingValue
FROM TestingTable) t
As your original query is written now, your subquery will return 1 value overall, so your sum would be 1 or 0 always, not to mention it is illegal. To get around that, this SQL will apply the case statement to every row in the TestingTable and insert the result into a derived table (t), then the 'outer' select will sum the results. Hope this helps!
I'm having a bit of an issue with some derived tables that I hope someone will be able to help with. What I've got is 2 derived tables inside a select statement that then uses a pivot to display the results horizontally rather than vertically.
What I've got so far is:
SELECT * FROM(
SELECT SUM(Value) AS TotDays, ClassId FROM MainTable GROUP BY ClassId)
Union All
SELECT SUM(NumDays) As TotDays, ClassId FROM (
SELECT CASE WHEN COUNT(SiteId) > 0 THEN 1 ELSE 0 END AS NumDays
FROM Table2 GROUP BY ClassId ) as SUB
) AS a
PIVOT (SUM(TotDays) FROM ClassId
IN ([12],[13],[14],[15]
What I'm trying to do is reference the individual columns rather than using SELECT *, but I don't know how to do it. I can make it work without if I drop everything from the union onwards, but when I put the union in it doesn't work and I have to use SELECT *.
Anyone got any ideas on what's going wrong?
Thanks
Alex
You have a couple of errors on your query. For example, your UNION ALL has sets with a different number of columns, and you have other syntax errors. Try this way:
SELECT [12],[13],[14],[15]
FROM ( SELECT SUM(Value) AS TotDays, ClassId
FROM MainTable
GROUP BY ClassId
UNION ALL
SELECT SUM(NumDays) As TotDays, ClassId
FROM ( SELECT CASE WHEN COUNT(SiteId) > 0 THEN 1 ELSE 0 END NumDays,
ClassId
FROM Table2
GROUP BY ClassId) as SUB
) AS a
PIVOT (SUM(TotDays) FROM ClassId IN ([12],[13],[14],[15])) AS PT
SELECT
MyColumn = 'something'
FROM table
WHERE MyColumn == 'something'
Possible to use MyColumn in WHERE clause?
EDIT:
Here's full query:
select TOP 10
PremiumYTDCurrent=Sum(CASE WHEN
AASI.Inv_Acctcur>='201101'
and AASI.Inv_Acctcur<='201102'
THEN (AASI.Inv_Premium)*R.[Percent]
ELSE 0 END),
PremiumYTDPrevious=Sum(CASE WHEN
AASI.Inv_Acctcur>='201001'
and AASI.Inv_Acctcur<='201002'
THEN (AASI.Inv_Premium)*R.[Percent]
ELSE 0 END),
R.STAFF, L.Description, L.LINE_OF_BUSINESS
from AAS_Invoice AASI,Invoice I,Revenue_Tracking R, Policy P, Line_Of_Business L
where I.Invoice_No=convert(Char,Convert(int,AASI.Inv_Entry_Num))
and I.Invoice=R.Invoice
and I.POLICY=P.POLICY
and L.LINE_OF_BUSINESS=P.LINE_OF_BUSINESS
and R.Organization IN (SELECT ST.ORGANIZATION FROM Staff ST WHERE ST.STAFF=14407)
and R.Staff=14407
and R.Activity_type='Broker'
and R.[Percent]>0
and PremiumYTDCurrent != 0
group by R.STAFF, L.Description, L.LINE_OF_BUSINESS
order by PremiumYTDCurrent DESC, PremiumYTDPrevious DESC, average_policy DESC
You can not use the column in the where clause. Use the expression instead.
and Sum(CASE WHEN
AASI.Inv_Acctcur>='201101'
and AASI.Inv_Acctcur<='201102'
THEN (AASI.Inv_Premium)*R.[Percent]
ELSE 0 END) <> 0
Edit 1
Did not notice the SUM clause.
Try add it as a HAVING clause instead after order by.
having Sum(CASE WHEN
AASI.Inv_Acctcur>='201101'
and AASI.Inv_Acctcur<='201102'
THEN (AASI.Inv_Premium)*R.[Percent]
ELSE 0 END) != 0
You could wrap the SQL up in a nested statement, a horrendously simple example being, e.g.:
SELECT MyMadeUpColumnName, col2, AnotherMadeUpColumn FROM (
SELECT SUM(sillycolumn) AS 'MyMadeUpColumnName', col2 FROM table GROUP BY col2
) AS t
WHERE t.AnotherMadeUpColumn <> 0
Any column names that you (re)define in the derived table become the actual column names for the parent select.
I am trying to have a running average column in the SELECT statement based on a column from the n previous rows in the same SELECT statement. The average I need is based on the n previous rows in the resultset.
Let me explain
Id Number Average
1 1 NULL
2 3 NULL
3 2 NULL
4 4 2 <----- Average of (1, 3, 2),Numbers from previous 3 rows
5 6 3 <----- Average of (3, 2, 4),Numbers from previous 3 rows
. . .
. . .
The first 3 rows of the Average column are null because there are no previous rows. The row 4 in the Average column shows the average of the Number column from the previous 3 rows.
I need some help trying to construct a SQL Select statement that will do this.
This should do it:
--Test Data
CREATE TABLE RowsToAverage
(
ID int NOT NULL,
Number int NOT NULL
)
INSERT RowsToAverage(ID, Number)
SELECT 1, 1
UNION ALL
SELECT 2, 3
UNION ALL
SELECT 3, 2
UNION ALL
SELECT 4, 4
UNION ALL
SELECT 5, 6
UNION ALL
SELECT 6, 8
UNION ALL
SELECT 7, 10
--The query
;WITH NumberedRows
AS
(
SELECT rta.*, row_number() OVER (ORDER BY rta.ID ASC) AS RowNumber
FROM RowsToAverage rta
)
SELECT nr.ID, nr.Number,
CASE
WHEN nr.RowNumber <=3 THEN NULL
ELSE ( SELECT avg(Number)
FROM NumberedRows
WHERE RowNumber < nr.RowNumber
AND RowNumber >= nr.RowNumber - 3
)
END AS MovingAverage
FROM NumberedRows nr
Assuming that the Id column is sequential, here's a simplified query for a table named "MyTable":
SELECT
b.Id,
b.Number,
(
SELECT
AVG(a.Number)
FROM
MyTable a
WHERE
a.id >= (b.Id - 3)
AND a.id < b.Id
AND b.Id > 3
) as Average
FROM
MyTable b;
Edit: I missed the point that it should average the three previous records...
For a general running average, I think something like this would work:
SELECT
id, number,
SUM(number) OVER (ORDER BY ID) /
ROW_NUMBER() OVER (ORDER BY ID) AS [RunningAverage]
FROM myTable
ORDER BY ID
A simple self join would seem to perform much better than a row referencing subquery
Generate 10k rows of test data:
drop table test10k
create table test10k (Id int, Number int, constraint test10k_cpk primary key clustered (id))
;WITH digits AS (
SELECT 0 as Number
UNION SELECT 1
UNION SELECT 2
UNION SELECT 3
UNION SELECT 4
UNION SELECT 5
UNION SELECT 6
UNION SELECT 7
UNION SELECT 8
UNION SELECT 9
)
,numbers as (
SELECT
(thousands.Number * 1000)
+ (hundreds.Number * 100)
+ (tens.Number * 10)
+ ones.Number AS Number
FROM digits AS ones
CROSS JOIN digits AS tens
CROSS JOIN digits AS hundreds
CROSS JOIN digits AS thousands
)
insert test10k (Id, Number)
select Number, Number
from numbers
I would pull the special case of the first 3 rows out of the main query, you can UNION ALL those back in if you really want it in the row set. Self join query:
;WITH NumberedRows
AS
(
SELECT rta.*, row_number() OVER (ORDER BY rta.ID ASC) AS RowNumber
FROM test10k rta
)
SELECT nr.ID, nr.Number,
avg(trailing.Number) as MovingAverage
FROM NumberedRows nr
join NumberedRows as trailing on trailing.RowNumber between nr.RowNumber-3 and nr.RowNumber-1
where nr.Number > 3
group by nr.id, nr.Number
On my machine this takes about 10 seconds, the subquery approach that Aaron Alton demonstrated takes about 45 seconds (after I changed it to reflect my test source table) :
;WITH NumberedRows
AS
(
SELECT rta.*, row_number() OVER (ORDER BY rta.ID ASC) AS RowNumber
FROM test10k rta
)
SELECT nr.ID, nr.Number,
CASE
WHEN nr.RowNumber <=3 THEN NULL
ELSE ( SELECT avg(Number)
FROM NumberedRows
WHERE RowNumber < nr.RowNumber
AND RowNumber >= nr.RowNumber - 3
)
END AS MovingAverage
FROM NumberedRows nr
If you do a SET STATISTICS PROFILE ON, you can see the self join has 10k executes on the table spool. The subquery has 10k executes on the filter, aggregate, and other steps.
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Check out some solutions here. I'm sure that you could adapt one of them easily enough.
If you want this to be truly performant, and arn't afraid to dig into a seldom-used area of SQL Server, you should look into writing a custom aggregate function. SQL Server 2005 and 2008 brought CLR integration to the table, including the ability to write user aggregate functions. A custom running total aggregate would be the most efficient way to calculate a running average like this, by far.
Alternatively you can denormalize and store precalculated running values. Described here:
http://sqlblog.com/blogs/alexander_kuznetsov/archive/2009/01/23/denormalizing-to-enforce-business-rules-running-totals.aspx
Performance of selects is as fast as it goes. Of course, modifications are slower.