Conditional WHERE clause with CASE statement in Oracle - sql

I'm brand-new to the Oracle world so this could be a softball. In working with an SSRS report, I'm passing in a string of states to a view. The twist is that the users could also pick a selection from the state list called "[ No Selection ]" ... (that part was not by doing and I'm stuck with implementing things this way)
If they choose the No Selection option, then I just want to return all states by default, otherwise return just the list of states that are in my comma-separated list.
This really seems like it should be easy but I'm stuck. Here is the code I have so far (just trying to get a sample to work) but my eyes have finally gone crossed trying to get it going.
Could anybody give me some direction on this one please?
begin
:stateCode:='MO,FL,TX';
--:stateCode:='[ No Selection ]';
end;
/
select count(*) as StateCount, :stateCode as SelectedVal
from hcp_state vw
where
(case
when (:stateCode = '') then (1)
when (:stateCode != '') then (vw.state_cd in (:stateCode))
(else 0)
end)
;

You can write the where clause as:
where (case when (:stateCode = '') then (1)
when (:stateCode != '') and (vw.state_cd in (:stateCode)) then 1
else 0)
end = 1;
Alternatively, remove the case entirely:
where (:stateCode = '') or
((:stateCode != '') and vw.state_cd in (:stateCode));
Or, even better:
where (:stateCode = '') or vw.state_cd in (:stateCode)

We can use a CASE statement in WHERE clause as:
SELECT employee_no, name, department_no
FROM emps
WHERE (CASE
WHEN :p_dept_no = 50 THEN 0
WHEN :p_dept_no = 70 THEN 0
ELSE -1
END) = 0;

Related

How to skip column output based on value?

I am using following script to generate objects in C# from Oracle and it works ok.
select 'yield return new Question { QuestionID = '||Q.questionid||', Qcode = "'||Q.Qcode||'", QuestionDescription = "'||Q.questiondescription||'", QuestionText = "'||Q.questiontext||'", QuestionCategoryId = '||Q.questioncategoryid||', QuestionTypeID = '||Q.QuestionTypeID||', IsThunderheadOnly = '|| case q.isthunderheadonly when 0 then 'false' else 'true' end ||', DisplayOrder = '||q.displayorder||' };'
from QUESTION q
where
questioncategoryid = 7
However again and again I run into the problem where I cannot || add columns with NULL values and solution to this point was adding those properties manually, which was ok when selecting up to 20 records.
Now I ran into a case of having to select hundreds of records and adding them manually would take substantial amount of time.
How could I modify the script to add (example) MaxValue property if column in the table is NOT NULL but skip it it if it is?
You can skip it with case ... when ... else like you figured out by yourself:
... ||case when A.NEXTQUESTIONID is not null then 'NextQuestionID = '||A.NEXTQUESTIONID||',' else '' end || ...
You can also use the nvl2 function for a shorter solution:
... || nvl2(A.NEXTQUESTIONID, 'NextQuestionID = '||A.NEXTQUESTIONID||',', '') || ...

MSSQL 2008: Problems with the 'Case' - statement

I'm having some troubles finding a solution to my SQL-Problem. I've tried google but so far my search didn't give me any statisfactory results.
I have an SSRS report with two parameters:
#SupplierId NVARCHAR (May contain NULL)
#EmployeeId NVARCHAR (May contain NULL)
My original query retrieved all the employees who came in service during the last year:
SELECT Name, Surname from dbo.Employee Where Employee.DateInService > DATEADD(year,-1,GETDATE())
Right now i want to add those parameters to the query using the following logic.
Remark this is pseudo SQL:
SELECT
...
FROM ...
WHERE Employee.DateInService > DATEADD(year,-1,GETDATE()) AND
IF (LEN(RTRIM(#SupplierId)) = 0 Or #SupplierID IS NULL ) THEN
dbo.Employee.EmployeeId = #EmployeeId
Else
dbo.Employee.SupplierId = #SupplierId
My search sofar led me to the Case statement. I made a query which contains an syntax error (obviously). My base query:
SELECT
...
FROM ...
WHERE Employee.DateInService > DATEADD(year,-1,GETDATE()) AND
CASE WHEN (LEN(RTRIM(#SupplierId)) = 0) THEN
dbo.Employee.EmployeeId = #EmployeeId
Else
dbo.Employee.SupplierId = #SupplierId
Error: Syntax error near '='.
Question 1: Why does he give an error near the '='?
Question 2: How do i correctly implement the following:
CASE WHEN (LEN(RTRIM(#SupplierId)) = 0 "Or #SupplierId is null" ) THEN
Instead of
CASE WHEN (LEN(RTRIM(#SupplierId)) = 0) Then dbo.Employee.EmployeeId = #EmployeeId
WHEN (#SupplierId IS NULL) Then dbo.Employee.EmployeeId = #EmployeeId
ELSE dbo.Employee.EmployeeId = #EmployeeId END
Note: if i've missed a post during my google searches, please don't hesitate to point it out.
Thanks for your help
You can't change the actual query predicate like that with CASE - there are 2 distinct queries depending on the value of #SupplierId. You can conditionally apply the filter as follows (I've assumed the #SupplierId = null flow is the same as the whitespace branch:
SELECT
...
FROM ...
WHERE Employee.DateInService > DATEADD(year,-1,GETDATE())
AND
(
(dbo.Employee.EmployeeId = #EmployeeId
AND (LEN(RTRIM(#SupplierId)) = 0 OR #SupplierId IS NULL))
OR
(dbo.Employee.SupplierId = #SupplierId AND LEN(RTRIM(#SupplierId)) > 0)
)
Although this can be prone to query plan sniffing related performance issues, in which case you might need to consider an alternative approach, e.g. using parameterized dynamic sql to build up and execute the sql, as there are 2 distinct process flows through the query.
Edit
As per Ypercube's comment above, in order to provide the boolean result needed for the predicate, if you can find a hack workaround is to find a way to project a COMMON scalar from each of the CASE .. WHEN row and then do a comparison of the scalar. In the example below, projecting a yes / no flag.
SELECT * FROM dbo.Employee
WHERE
CASE
WHEN (LEN(RTRIM(#SupplierId)) = 0 OR #SupplierId IS NULL)
THEN CASE WHEN dbo.Employee.EmployeeId = #EmployeeId THEN 1 ELSE 0 END
ELSE CASE WHEN dbo.Employee.SupplierId = #SupplierId THEN 1 ELSE 0 END
END = 1;
But the big problem with this approach is performance - the above will require a full scan to determine the results.

Oracle function error

I am typing a function and i'm having an error here, I dont know what it is.
Could you give me a Hand ?
CREATE or replace FUNCTION function1(pIdReg in number,pIdPeriod in number) RETURN
number
IS
ncv number DEFAULT 0;
BEGIN
SELECT COUNT(IdPeriod)
INTO ncv
FROM(
SELECT a.IdPeriod, SUM(case when a.nt=0 then -a.valor else a.valor end) AS total --IF(a.nt=0,-a.valor,a.valor))
FROM dc a
JOIN emp b ON a.idDoc = b.idDoc
WHERE a.idReg = pIdReg AND a.IdPeriod < pIdPeriod AND
b.cc != 305 AND
(
b.cc = 302 AND(b.tipomov != 4)
OR
b.cc != 302 AND(1=1)-- emular el TRUE
)
AND a.type != 7
GROUP BY 1 HAVING total != 0
) AS ncv;
RETURN ncv;
END;
/
The error is SQL command not properly ended.
Sqldeveloper shows "AS ncv" underlined. Is there any problem with group by or having clause ?
I see three errors (though there may be more)
Oracle does not use the AS keyword for assigning table aliases. So AS ncv is invalid. If you want to use ncv as the alias for your subquery, you'd need to remove the AS (though it seems odd to choose an alias that happens to collide with the name of a local variable).
You cannot use positional notation in a GROUP BY clause. You would need to specify the name of the column(s) you want to group by not their position.
You cannot use aliases defined in your SELECT list in your HAVING clause. You would have to specify the aggregate function in the HAVING clause
Putting those three things together, I suspect you want something like this
CREATE or replace FUNCTION function1(pIdReg in number,pIdPeriod in number)
RETURN number
IS
ncv number DEFAULT 0;
BEGIN
SELECT COUNT(IdPeriod)
INTO ncv
FROM(
SELECT a.IdPeriod,
SUM(case when a.nt=0
then -a.valor
else a.valor
end) AS total --IF(a.nt=0,-a.valor,a.valor))
FROM dc a
JOIN emp b ON a.idDoc = b.idDoc
WHERE a.idReg = pIdReg AND a.IdPeriod < pIdPeriod
AND b.cc != 305
AND (
b.cc = 302 AND(b.tipomov != 4)
OR
b.cc != 302 AND(1=1)-- emular el TRUE
)
AND a.type != 7
GROUP BY a.IdPeriod
HAVING SUM(case when a.nt=0
then -a.valor
else a.valor
end) != 0
) ncv;
RETURN ncv;
END;
/
If you are still getting errors, it would be extremely helpful if you could edit your question and provide the DDL to create the tables that are referenced in this code. That would allow us to test on our systems whether the function compiles or not rather than trying to guess at the syntax errors

Nhibernate Criteria Conditional Where

Im working on a NHibernate criteria wich i graduatly builds upp depending on input parameters.
I got some problem with the postal section of these paramters.
Since we got a 5 number digit zipcodes the input parameter is a int, but since we in database also accept foreign zipcodes the database saves it as string.
What im trying to replicate in NHibernate Criteria/Criterion is the following where clause.
WHERE
11182 <=
(case when this_.SendInformation = 0 AND dbo.IsInteger(this_.Zipcode) = 1 then
CAST(REPLACE(this_.Zipcode, ' ', '') AS int)
when this_.SendInformation = 1 AND dbo.IsInteger(this_.WorkZipcode) = 1 then
CAST(REPLACE(this_.WorkZipcode, ' ', '') AS int)
when this_.SendInformation = 2 AND dbo.IsInteger(this_.InvoiceZipcode) = 1 then
CAST(REPLACE(this_.InvoiceZipcode, ' ', '') AS int)
else
NULL
end)
What we do is to check where the member contact (this_) has preferenced to get information sent to, then we check the input zipcode as integer against three different columns depending on if the column is convertable to int (IsInteger(expr) function) if column is not convertable we mark the side as NULL
in this case we just check if the zipcode is >= input parameter (reversed in sql code since paramter is first), the goal is to do a between (2 clauses wrapped with 'AND' statement), >= or <=.
UPDATE
Got a hint of success.
Projections.SqlProjection("(CASE when SendInformation = 0 AND dbo.IsInteger(Zipcode) = 1 then CAST(REPLACE(Zipcode, ' ', '') AS int) when SendInformation = 1 AND dbo.IsInteger(WorkZipcode) = 1 then CAST(REPLACE(WorkZipcode, ' ', '') AS int) when SendInformation = 2 AND dbo.IsInteger(InvoiceZipcode) = 1 then CAST(REPLACE(InvoiceZipcode, ' ', '') AS int) else NULL END)"
, new[] { "SendInformation", "Zipcode", "WorkZipcode", "InvoiceZipcode" },
new[] { NHibernateUtil.Int32, NHibernateUtil.String, NHibernateUtil.String, NHibernateUtil.String });
Throw my whole clause in a Projections.SqlProjection, however when i run my code some of my projection is cut (" AS int) else NULL END)" is cut from the end) and makes the sql corrupt.
Is there some kind of limit on this ?
Got it working yesterday.
Projections.SqlProjection worked, however if you don't name the projection as a column it some how cuts some of the TSQL code.
(Case
when x = 1 then 'bla'
when x = 2 then 'bla_bla'
else NULL
END) as foo
when using the last part (as foo) and naming the entire case syntax it works and dont cut anything.
However i dont know why but i could not manage to use the aliases from the other part of the criteria.

ISNULL, SQL, Using a select statement as the second parameter

I don't know if this is possible in SQL or if I have to write a stored procedure but I'm trying to use the ISNULL function as below so that when the parameter #sku is null I'm using a select statement to bring back all the sku's in the table:
SELECT GooglePrice.idGooglePrice, GooglePrice.idProduct, products.sku, products.wholeprice, products.price as CurrentHMMPrice, GooglePrice.bestPrice, GooglePrice.link, GooglePrice.title, GooglePrice.description, GooglePrice.ourPrice as PriceCompHMMPrice,
GooglePrice.searchType, GooglePrice.shippingCost, GooglePrice.cheapestOrder, GooglePrice.timeStamp,
'ShippingCostNew' = CASE
WHEN GooglePrice.shippingCost = -1 THEN 'N/A'
WHEN GooglePrice.shippingCost = 0 THEN 'Free Shipping'
WHEN GooglePrice.shippingCost > 0 Then cast(GooglePrice.shippingCost as varchar)
END
FROM GooglePrice INNER JOIN
products ON GooglePrice.idProduct = products.idProduct
WHERE (products.supplierCode in (#SupplierCode)) AND ISNULL((products.sku like '%'+#sku+'%'), (products.sku in (select sku from products where products.sku)))
ORDER BY GooglePrice.idGooglePrice
Would be easier with an OR
WHERE
(products.supplierCode in (#SupplierCode))
AND
(products.sku like '%'+#SupplierCode+'%' OR #SupplierCode IS NULL)
This was your intention, no?
AND
products.sku like ISNULL('%'+#SupplierCode+'%',products.sku)
Notes:
leading wildcards can not be optimised and won't use indexes.
I assume you don't have a CSV in #SupplierCode for this products.supplierCode in (#SupplierCode)
Don't overcomplicate it.
Make your WHERE clause:
WHERE
((products.supplierCode in (#SupplierCode)
AND
(products.sku like '%'+#SupplierCode+'%'))
OR (#suppliercode IS NULL)
You don't really explain your logic so I'm guessing, but the idea is to put a separate check for the NULL comparison.
SELECT GooglePrice.idGooglePrice, GooglePrice.idProduct, products.sku, products.wholeprice, products.price as CurrentHMMPrice, GooglePrice.bestPrice, GooglePrice.link, GooglePrice.title, GooglePrice.description, GooglePrice.ourPrice as PriceCompHMMPrice, GooglePrice.searchType, GooglePrice.shippingCost, GooglePrice.cheapestOrder, GooglePrice.timeStamp,
'ShippingCostNew' = CASE
WHEN GooglePrice.shippingCost = -1 THEN 'N/A'
WHEN GooglePrice.shippingCost = 0 THEN 'Free Shipping'
WHEN GooglePrice.shippingCost > 0 Then cast(GooglePrice.shippingCost as varchar)
END
FROM GooglePrice INNER JOIN
products ON GooglePrice.idProduct = products.idProduct
WHERE (products.supplierCode in (#SupplierCode)) AND (#SupplierCode is null or products.sku like '%'+#SupplierCode+'%')
ORDER BY GooglePrice.idGooglePrice