Case Statement in SQL Server - sql

I am learning SQL case statements and have the following stored procedure.
Select PT.[ID] 'TransactionID', PT.BatchNumber, PT.SequenceNumber, PT.TransactionDate,
PT.TerminalID, PT.TotalAmount, PT.TransactionTypeID, TT.TransactionType,
PT.PAN 'EmbossLine',PT.PreBalanceAmount, PT.PostBalanceAmount, RefTxnID, SettlementDate,PaidCash, CreditAmount, DiscountAmount,
RefPAN, Remarks, PT.Product,
case PT.Product when 1 then 'Taxi' end 'ProductName'
case PT.Product when 2 then 'Airport Lounge' end 'ProductName'
into #Temp
from POS_Transactions PT inner join TransactionType TT on TT.TransactionTypeID = PT.TransactionTypeID
where
PT.[ID] not in (Select distinct isnull(TransactionID,0) from Testcards)
and (PT.TransactionDate >= #DateFrom)
and (PT.TransactionDate < #DateTo)
and (PT.TransactionTypeID = #TransactionTypeID or #TransactionTypeID = -999)
select T.*, C.EmbossLine+' ' as 'EmbossLine', C.EmbossLine as 'EmbossLine1',
C.EmbossName, PM.MerchantID, PM.MerchantName1, C.AccountNumber, C.VehicleNumber
from #Temp T
inner join Card C on C.EmbossLine= T.EmbossLine
inner join Terminal on Terminal.TerminalID = T.TerminalID
inner join Merchant PM on PM.MerchantID = Terminal.MerchantID
where C.Status <>'E3'
and C.CardID not in (Select distinct isnull(CardID,0) from Testcards)
and (PM.MerchantID =#MerchantID or #MerchantID='-999')
and (C.EmbossLine like '%'+#EmbossLine+'%' or #EmbossLine like '-999')
and (C.EmbossName like '%'+#EmbossName+'%' or #EmbossName like '-999')
order by T.TransactionDate, MerchantName1, T.BatchNumber, T.SequenceNumber
drop table #Temp
When I create it, command is executed succesfully. However when I call it, it throws following error
Column names in each table must be unique. Column name 'ProductName'
in table '#Temp' is specified more than once.
I think I have problem in the syntax in these lines
case PT.Product when 1 then 'Taxi' end 'ProductName'
case PT.Product when 2 then 'Airport Lounge' end 'ProductName'
Can someone identify?

Your line is indeed a problem.
I suspect you're after something like:
case PT.Product
when 1 then 'Taxi'
when 2 then 'Airport Lounge'
end 'ProductName'
In your syntax you make two different cases, resulting in two columns being selected, both called the same.
Above the case can return two different values into the one row.

Related

Attempting to use result of Case Expression in a join .. need to improve query

I have the following query which allows me to join the TransactionClass tables base on TransactionClassID from either the primary table (Transactions) or TransactionRules based on a condition as below:
SELECT
Description,
TC.Name,
(CASE
WHEN (TR.TransactionRuleId > 0)
THEN TR.TransactionRuleId
ELSE T.TransactionClassId
END) As ClassId
FROM Transactions AS T
LEFT JOIN TransactionRules TR ON T.Description LIKE TR.Pattern
LEFT JOIN TransactionClasses TC ON TC.TransactionClassId =
(CASE
WHEN (TR.TransactionRuleId > 0)
THEN TR.TransactionClassId
ELSE T.TransactionClassId
END)
The query is running on SQL Server,
In effect, it retrieves the correct TransactionClass entry depending on whether or not the join on TransactionRules was successful or not.
The above query works, but I am trying to simplify the query so that I do not have to repeat the CASE expression in two places.
I attempted to capture the result of the case expression in a variable and use that as follows:
SELECT
Description,
x
FROM Transactions AS T
LEFT JOIN TransactionRules TR
ON T.Description LIKE TR.Pattern
LEFT JOIN TransactionClasses TC
ON TC.TransactionClassId = x
WHERE x = (CASE
WHEN (TR.TransactionRuleId > 0)
THEN TR.TransactionRuleId
ELSE T.TransactionClassId
END)
But I get the error:
[S0001][207] Line 8: Invalid column name 'x'.
Where am I going wrong in my attempt to have only one CASE Expression?
CROSS APPLY is a tidy way to reuse a calculated value e.g.
SELECT
[Description]
, TC.[Name]
, Class.Id
FROM Transactions AS T
LEFT JOIN TransactionRules TR ON T.[Description] LIKE TR.Pattern
CROSS APPLY (
VALUES (
CASE
WHEN TR.TransactionRuleId > 0
THEN TR.TransactionRuleId
ELSE T.TransactionClassId
END
)
) AS Class (Id)
LEFT JOIN TransactionClasses TC ON TC.TransactionClassId = Class.Id;

How to use a non-existing column in sql query

I am working in SQL server 2012. I have to write a sql statement where I first assign a value to [Pay_Type], which is a non-existing column (not sure whether it can be called as variable or not) and based upon its value I want to use it in another case statement as shown below
SELECT sp.First_Name, [Pay_Type] = CASE WHEN NOT EXISTS(SELECT '1' FROM
PERSON_SALARY ps WHERE ps.PARTY_ID = sp.PARTY_ID and ps.END_DATE IS NULL)
THEN 'Hourly' ELSE 'Salary' END,
HOURLY_RATE = CASE WHEN [Pay_Type] = 'Hourly' THEN pj.HOURLY_RATE ELSE
'0.00' END
FROM SEC_PERSON sp
LEFT OUTER JOIN PERSON_JOB pj ON sp.PERSON_ID = pj.PERSON_ID
WHERE sp.END_DATE IS NOT NULL
But I am getting "Invalid column name 'Pay_Type' " error.
Column aliases cannot be re-used in the same SELECT where they are define. The typical answer is to use a subquery or CTE. I also like using a lateral join:
SELECT sp.First_Name, s.Pay_Type,
HOURLY_RATE = (CASE WHEN s.Pay_Type = 'Hourly' THEN pj.HOURLY_RATE ELSE
'0.00' END)
FROM SEC_PERSON sp LEFT OUTER JOIN
PERSON_JOB pj
ON sp.PERSON_ID = pj.PERSON_ID OUTER APPLY
(SELECT (CASE WHEN NOT EXISTS (SELECT 1
FROM PERSON_SALARY ps
WHERE ps.PARTY_ID = sp.PARTY_ID and ps.END_DATE IS NULL
)
THEN 'Hourly' ELSE 'Salary'
END) as PayType
) s
WHERE sp.END_DATE IS NOT NULL

SQL Server / T-SQL : query optimization assistance

I have this QA logic that looks for errors into every AuditID within a RoomID to see if their AuditType were never marked Complete or if they have two complete statuses. Finally, it picks only the maximum AuditDate of the RoomIDs with errors to avoid showing multiple instances of the same RoomID, since there are many audits per room.
The issue is that the AUDIT table is very large and takes a long time to run. I was wondering if there is anyway to reach the same result faster.
Thank you in advance !
IF object_ID('tempdb..#AUDIT') is not null drop table #AUDIT
IF object_ID('tempdb..#ROOMS') is not null drop table #ROOMS
IF object_ID('tempdb..#COMPLETE') is not null drop table #COMPLETE
IF object_ID('tempdb..#FINALE') is not null drop table #FINALE
SELECT distinct
oc.HotelID, o.RoomID
INTO #ROOMS
FROM dbo.[rooms] o
LEFT OUTER JOIN dbo.[hotels] oc on o.HotelID = oc.HotelID
WHERE
o.[status] = '2'
AND o.orderType = '2'
SELECT
t.AuditID, t.RoomID, t.AuditDate, t.AuditType
INTO
#AUDIT
FROM
[dbo].[AUDIT] t
WHERE
t.RoomID IN (SELECT RoomID FROM #ROOMS)
SELECT
t1.RoomID, t3.AuditType, t3.AuditDate, t3.AuditID, t1.CompleteStatus
INTO
#COMPLETE
FROM
(SELECT
RoomID,
SUM(CASE WHEN AuditType = 'Complete' THEN 1 ELSE 0 END) AS CompleteStatus
FROM
#AUDIT
GROUP BY
RoomID) t1
INNER JOIN
#AUDIT t3 ON t1.RoomID = t3.RoomID
WHERE
t1.CompleteStatus = 0
OR t1.CompleteStatus > 1
SELECT
o.HotelID, o.RoomID,
a.AuditID, a.RoomID, a.AuditDate, a.AuditType, a.CompleteStatus,
c.ClientNum
INTO
#FINALE
FROM
#ROOMS O
LEFT OUTER JOIN
#COMPLETE a on o.RoomID = a.RoomID
LEFT OUTER JOIN
[dbo].[clients] c on o.clientNum = c.clientNum
SELECT
t.*,
Complete_Error_Status = CASE WHEN t.CompleteStatus = 0
THEN 'Not Complete'
WHEN t.CompleteStatus > 1
THEN 'Complete More Than Once'
END
FROM
#FINALE t
INNER JOIN
(SELECT
RoomID, MAX(AuditDate) AS MaxDate
FROM
#FINALE
GROUP BY
RoomID) tm ON t.RoomID = tm.RoomID AND t.AuditDate = tm.MaxDate
One section you could improve would be this one. See the inline comments.
SELECT
t1.RoomID, t3.AuditType, t3.AuditDate, t3.AuditID, t1.CompleteStatus
INTO
#COMPLETE
FROM
(SELECT
RoomID,
COUNT(1) AS CompleteStatus
-- Use the above along with the WHERE clause below
-- so that you are aggregating fewer records and
-- avoiding a CASE statement. Remove this next line.
--SUM(CASE WHEN AuditType = 'Complete' THEN 1 ELSE 0 END) AS CompleteStatus
FROM
#AUDIT
WHERE
AuditType = 'Complete'
GROUP BY
RoomID) t1
INNER JOIN
#AUDIT t3 ON t1.RoomID = t3.RoomID
WHERE
t1.CompleteStatus = 0
OR t1.CompleteStatus > 1
Just a thought. Streamline your code and your solution. you are not effectively filtering your datasets smaller so you continue to query the entire tables which is taking a lot of your resources and your temp tables are becoming full copies of those columns without the indexes (PK, FK, ++??) on the original table to take advantage of. This by no means is a perfect solution but it is an idea of how you can consolidate your logic and reduce your overall data set. Give it a try and see if it performs better for you.
Note this will return the last audit record for any room that has either not had an audit completed or completed more than once.
;WITH cte AS (
SELECT
o.RoomId
,o.clientNum
,a.AuditId
,a.AuditDate
,a.AuditType
,NumOfAuditsComplete = SUM(CASE WHEN a.AuditType = 'Complete' THEN 1 ELSE 0 END) OVER (PARTITION BY o.RoomId)
,RowNum = ROW_NUMBER() OVER (PARTITION BY o.RoomId ORDER BY a.AuditDate DESC)
FROm
dbo.Rooms o
LEFT JOIN dbo.Audit a
ON o.RoomId = a.RoomId
WHERE
o.[Status] = 2
AND o.OrderType = 2
)
SELECT
oc.HotelId
,cte.RoomId
,cte.AuditId
,cte.AuditDate
,cte.AuditType
,cte.NumOfAuditsComplete
,cte.clientNum
,Complete_Error_Status = CASE WHEN cte.NumOfAuditsComplete > 1 THEN 'Complete More Than Once' ELSE 'Not Complete' END
FROM
cte
LEFT JOIN dbo.Hotels oc
ON cte.HotelId = oc.HotelId
LEFT JOIN dbo.clients c
ON cte.clientNum = c.clientNum
WHERE
cte.RowNum = 1
AND cte.NumOfAuditsComplete != 1
Also note I changed your
WHERE
o.[status] = '2'
AND o.orderType = '2'
TO
WHERE
o.[status] = 2
AND o.orderType = 2
to be numeric without the single quotes. If the data type is truely varchar add them back but when you query a numeric column as a varchar it will do data conversion and may not take advantage of indexes that you have built on the table.

SQL Joining tables with 'constants'

I have a table of orders,
Invoice Location Customer Code SalesPersonEmail
------------------------------------------------------
300001 001 CUS001 ?
300002 006 CUS002 ?
And a table of email groups,
Role Email
-----------------------------------------------------
Filtered_Group Management#gmail.com;john#gmail.com
When Location = 001, SalesPersonEmail must be the Email field from Filtered_Group
SalesPersonEmail for all other locations must be "Orders#gmail.com;" + the Email for Role No_Filter_Group.
I'm currently using the following to achieve this,
SELECT i.Invoice, i.Location, i.[Customer Code],
CASE WHEN i.Location = 001
THEN f.Email
ELSE N'Orders#gmail.com;' + nf.Email as SalesPersonEmail
END
FROM Invoice i, RoleCodes f, RoleCodes nf
WHERE f.Role = N'Filtered_Group' AND nf.Role = N'No_Filter_Group'
My problem is the Role No_Filter_Group may not exist in the Role table at times, which causes the above query to return nothing.
How do I join these tables properly so if No_Filter_Group does not exist in the table, rows that have a SalesPersonEmail of Filtered_Group are still returned from the query?
Thanks
A relatively simple way is to use LEFT JOIN and put the special number 001 for your location and special role names Filtered_Group and No_Filter_Group in the join condition.
In this SQL Fiddle you can comment/uncomment one line in the schema definition to see how it works when RoleCodes has a row with No_Filter_Group and when it doesn't.
In any case, the query would return all rows from Invoice table.
SELECT
Invoice.Invoice
,Invoice.Location
,Invoice.[Customer Code]
,CASE WHEN Invoice.Location = '001'
THEN RoleCodes.Email
ELSE 'Orders#gmail.com;' + ISNULL(RoleCodes.Email, '')
END AS SalesPersonEmail
FROM
Invoice
LEFT JOIN RoleCodes ON
(Invoice.Location = '001'
AND RoleCodes.Role = 'Filtered_Group')
OR
(Invoice.Location <> '001'
AND RoleCodes.Role = 'No_Filter_Group')
Try something like this.
Note: This is just a example am not sure about the tables and column of your schema. Replace with the respective tables and columns
SELECT CASE
WHEN location = '001' THEN (SELECT TOP 1 email
FROM email_table
WHERE [role] = 'Filtered_Group')
ELSE 'Orders#gmail.com;'
END
FROM orders
If email_table table will have only one row for [role] = 'Filtered_Group' then you can remove the TOP 1 from the sub-query
Left join or an easier, albeit less efficient method would be to do a subquery in the select statement itself.
SELECT i.Invoice, i.Location, i.[Customer Code],
CASE WHEN i.Location = 001
THEN (SELECT TOP 1 f.Email FROM RoleCodes f WHERE f.Role = N'Filtered_Group')
ELSE N'Orders#gmail.com;' + ISNULL( (SELECT nf.Email as SalesPersonEmail FROM RoleCodes nf WHERE nf.Role = N'No_Filter_Group'), '')
END
FROM Invoice i
Normally you would want to join these in on each other but I'm not certain how you would do that with the schema provided.
Nested select will be run for each row, instead, you could try this :-
Select i.Invoice
,i.Location
,i.CustomerCode
,Isnull(r.Email,'Orders#gmail.com') As SalesPersonEmail
From Invoice As i With (Nolock)
Left Join
(
Select rc.Email
,'001' As Location
From RoleCodes As rc With (Nolock)
Where rc.Role = 'Filtered_Group'
) As r On i.Location = r.Location
use the following Query:
select t.Invoice,t.Location,t.[Customer Code],
case t.Location
when '001' then
t2.Email
else
'Orders#gmail.com'
end
as
Salespersonemail
from orders t
join email_groups t2 on t2.Role='Filtered_Group'

SQL Group By Join

I have three tables I need to join in order to tell what documents a product needs. Not all documents are needed on each product.
There is a Document table, a Product table, and a DocTracking table that tracks the documents associated with products
Product Table
ProdID ProdName
1 Ball
2 Wheel
DocTracking Table
ProdID DocID
1 1
1 2
2 2
I want the join to look like this:
ProdID ProdName Needs Word Doc? Needs Excel Doc?
1 Ball Yes Yes
2 Wheel No Yes
Any help would be appreciated, if I need to make this into a Stored Procedure, that is fine.
If you have only those documents and they are fix you can use this query:
SELECT ProdID, ProdName,
[Needs Word Doc] = CASE WHEN EXISTS(
SELECT 1 FROM Document d INNER JOIN DocTracking dt ON d.DocID=dt.DocID
WHERE dt.ProdID = p.ProdID AND d.[Doc Name] = 'Word Document'
) THEN 'Yes' ELSE 'No' END,
[Needs Excel Doc] = CASE WHEN EXISTS(
SELECT 1 FROM Document d INNER JOIN DocTracking dt ON d.DocID=dt.DocID
WHERE dt.ProdID = p.ProdID AND d.[Doc Name] = ' Excel Spreadsheet'
) THEN 'Yes' ELSE 'No' END
FROM dbo.Product p
Of course you could also use the DocID, then the query doesn't depend on the name.
select P.ProdID, P.ProdName,
case
when DW.DocID is null then 'Yes'
else 'No'
end as NeedsWordDoc,
case
when DE.DocID is null then 'Yes'
else 'No'
end as NeedsExcelDoc
from Product P
left join DocTracking DTW on DTW.ProdId = P.ProdId
left join Document DW on DW.DocID = DTW.DocID
and DW.Name = 'Word Document'
left join DocTracking DTE on DTE.ProdId = P.ProdId
left join Document DE on DE.DocID = DTE.DocID
and DE.Name = 'Excel Spreadsheet'
This is a little more complicated than a typical pivot query. But, the only challenging part is determining which documents are included, and then getting 'Yes' or 'No' out.
The following does this with coalesce() and a conditional that checks for the presence of one type of document:
select pt.ProdId, pt.ProdName,
coalesce(MAX(case when dt.DocId = 1 then 'Yes' end), 'No') as "Needs Word Doc?",
coalesce(MAX(case when dt.DocId = 2 then 'Yes' end), 'No') as "Needs Excel Doc?"
from ProductTable pt left outer join
DocTracking dt
on dt.ProdId = dt.ProdId
group by pt.ProdId, pt.ProdName;
Note that SQL queries return a fixed number of columns. So, you cannot have a SQL query that simply returns a different number of columns based on what is present in the documents table. You can create a SQL query in a string and then use a database-specific command to run it.
may be this would help you - using pivot:
select ProdId, ProdName,
case when isnull([Word Document],0)<>0 then 'Yes'
else 'No'
end as [Needs Word Doc?],
case when isnull([Excel Spreadsheet],0)<>0 then 'Yes'
else 'No'
end as [Needs Excel Spreadsheet?]
from
(
select p.ProdId,p.ProdName,d.DocId,d.DocName from
#Prod p left join
#Track t
on p.ProdId=t.ProdId
inner join #Doc d
on t.DocId=d.DocId
)
as temp
pivot
(max(DocID)
For DocName in ([Word Document],[Excel Spreadsheet])
)
as pvt