I have three tables:
order
orderline (has orderID)
orderactions (has orderID)
Then I need SUM(of orderline.price) and SUM(of orderactions.price) per orderID.
When I used:
SELECT order.ID, SUM(orderlines.price), SUM(orderactions.price)
FROM order
LEFT JOIN orderlines ON orderlines.orderID=order.ID
LEFT JOIN orderactions ON orderactions.orderID=order.ID
WHERE order.ID=#orderID
GROUP BY order.ID
I got a result from orderactions which a equivalent to SUM(orderactions.price)*quantity of orderlines for this order.ID
Only solution I found, which given me a right result, are sub-query for every "SUM"-table:
SELECT order.ID
, (SELECT SUM(orderlines.price) FROM orderlines WHERE orderlines.orderId=order.ID)
, (SELECT SUM(orderactions.price) FROM orderactions WHERE orderactions.orderId=order.ID)
FROM order
WHERE order.ID=#orderID
Question: is there some other (faster) solution for this, because sub-queries are slow and we try to not using them?
Since your select only runs the two very simple subqueries once each, I'd say you're pretty close to optimal for your query. There is no need to add a JOIN unless the queries are correlated in some way.
The slow part about subqueries is usually that the database may (if you're not careful how you write your query) non obviously execute them more than once. This normally happens if they depend on external values that may change per row, ie when you JOIN them in some way.
Your subqueries are straight forward enough and not using any external values other than your constant, so in your case, they only execute once each, and there is nothing in them that is simplified by adding a JOIN.
depends of your data this way can be a solution:
SELECT order.ID,
SUM(CASE WHEN orderlines.orderID IS NOT NULL THEN orderlines.price ELSE 0 END),
SUM(CASE WHEN orderactions.orderID IS NOT NULL THEN orderactions.price ELSE 0 END)
FROM order
LEFT JOIN orderlines ON orderlines.orderID=order.ID
LEFT JOIN orderactions ON orderactions.orderID=order.ID
WHERE order.ID=#orderID
GROUP BY order.ID
Related
I need to get count for header. So I have table A which contain transaction records, and table B which contain status of the transaction. I want to accumulate the data to show table A result count based from table B. But currently I still cannot get the empty data too.
I have create a SQLFiddle here.
I want all the status is display with zero when data from table A is not there.
As you can see from the image above, status with TSID: 4 (Complete) is not listed with zero.
I have tried some script
SELECT
COUNT(CASE WHEN A.Status = 0 THEN 1 END) AS Pending,
COUNT(CASE WHEN A.Status = 1 THEN 1 END) AS Assigned,
COUNT(CASE WHEN A.Status = 2 THEN 1 END) AS Started,
.
.
.
.
But I don't want this way because on client, I use a loop and render display based from the result return from SQL.
I have try LEFT JOIN, LEFT OUTER JOIN but not as expected result. I'm not much good with SQL join part, frankly speaking.
You need a LEFT JOIN, but you must flip around the order of the tables
SELECT
TS.TSID,
TS.TSName,
COUNT(T.Status) as Total
FROM B TS
LEFT JOIN A T ON T.Status = TS.TSID
GROUP BY
TS.TSID,
TS.TSName
ORDER BY
TS.TSID ASC;
SQL Fiddle
You can also do this as a RIGHT JOIN with the original order, however this can cause confusion especially in the presence of other joins. And because joins are commutative, you can just swap them around. This is why right joins are very rarely used in practice.
Note also that the grouping is over TS.TSID as T.Status may be null in some cases.
When you want all the records from the second table in the join, even if there is no match in the first table you need RIGHT JOIN. I have also removed MAX(T.status) from ORDER BY because it does not produce the result you want.
SELECT TS.TSID,TS.TSName,
COUNT(T.Status) as Total
FROM A T
RIGHT JOIN B TS
ON Status=TS.TSID
GROUP BY T.Status,
TS.TSID,TS.TSName
ORDER BY
MAX(TS.TSID) ASC;
I currently have the below query written within Query Designer. I asked a question yesterday and it worked on its own but I would like to incorporate it into my existing report.
SELECT Distinct
i.ProductNumber
,i.ProductType
,i.ProductPurchaseDate
,ih.SalesPersonComputerID
,ih.SalesPerson
,ic2.FlaggedComments
FROM [Products] i
LEFT OUTER JOIN
(SELECT Distinct
MIN(c2.Comments) AS FlaggedComments
,c2.SalesKey
FROM [SalesComment] AS c2
WHERE(c2.Comments like 'Flagged*%')
GROUP BY c2.SalesKey) ic2
ON ic2.SalesKey = i.SalesKey
LEFT JOIN [SalesHistory] AS ih
ON ih.SalesKey = i.SalesKey
WHERE
i.SaleDate between #StartDate and #StopDate
AND ih.Status = 'SOLD'
My question yesterday was that I wanted a way to select only the first comment made for each sale. I have a query for selecting the flagged comments but I want both the first row and the flagged comment. They would both be pulling from the same table. This was the query provided and it worked on its own but I cant figure out how to make it work with my existing query.
SELECT a.DateTimeCommented, a.ProductNumber, a.Comments, a.SalesKey
FROM (
SELECT
DateTimeCommented, ProductNumber, Comments, SalesKey,
ROW_NUMBER() OVER(PARTITION BY ProductNumber ORDER BY DateTimeCommented) as RowN
FROM [SalesComment]
) a
WHERE a.RowN = 1
Thank you so much for your assistance.
You can use a combination of row-numbering and aggregation to get both the Flagged% comments, and the first comment.
You may want to change the PARTITION BY clause to suit.
DISTINCT on the outer query is probably spurious, on the inner query it definitely is, as you have GROUP BY anyway. If you are getting multiple rows, don't just throw DISTINCT at it, instead think about your joins and whether you need aggregation.
The second LEFT JOIN logically becomes an INNER JOIN due to the WHERE predicate. Perhaps that predicate should have been in the ON instead?
SELECT
i.ProductNumber
,i.ProductType
,i.ProductPurchaseDate
,ih.SalesPersonComputerID
,ih.SalesPerson
,ic2.FlaggedComments
,ic2.FirstComments
FROM [Products] i
LEFT OUTER JOIN
(SELECT
MIN(CASE WHEN c2.RowN = 1 THEN c2.Comments) AS FirstComments
,c2.SalesKey
,MIN(CASE WHEN c2.Comments like 'Flagged*%' THEN c2.Comments) AS FlaggedComments
FROM (
SELECT *,
ROW_NUMBER() OVER (PARTITION BY ProductNumber ORDER BY DateTimeCommented) as RowN
FROM [SalesComment]
) AS c2
GROUP BY c2.SalesKey
) ic2 ON ic2.SalesKey = i.SalesKey
JOIN [SalesHistory] AS ih
ON ih.SalesKey = i.SalesKey
WHERE
i.SaleDate between #StartDate and #StopDate
AND ih.Status = 'SOLD'
Write a SELECT statement that returns two columns: VendorName and LargestInv
(LargestInv is the correlation name of the subquery)
Subquery portion:
SELECT statement that returns the largest InvoiceTotal from the Invoices table (you will need to perform the JOIN within the subquery in one of the clauses).
Sort the results by LargestInv from largest to smallest.(Subquery Must be in the Select statement)
I have tried this but My subqueries returning more than one value
USE AP
SELECT VendorName, (SELECT MAX(InvoiceTotal) FROM Invoices JOIN Vendors
ON Invoices.VendorID = Vendors.VendorID
GROUP BY Invoices.VendorID) AS LargestInv
FROM Vendors
Your issue is scope.
The sub-query shouldn't be joining to the Vendor table if the goal is a correlated sub-query. The "correlated" part comes from joining the results of the inner query (the sub-query) to the outer query.
As written, you're finding VendorID inside the sub-query and the results aren't correlated to the outer query at all. Hence your error message.
SELECT
VendorName,
(SELECT MAX(InvoiceTotal)
FROM Invoices
WHERE Invoices.VendorID = Vendors.VendorID
) AS LargestInv
FROM Vendors
ORDER BY LargestInv DESC;
Edit (extended explanation):
A correlated sub-query isn't designed to pull up a full result set, like the sub-query you were writing at first. It's designed to go over to another table and use a value (or values) from the outer query to bring back a single result, one row at a time.
In this case, using the VendorID from the Vendors table, go over to Invoices, calculate a MAX value "WHERE" the VendorID in Invoices matches the VendorID ON THIS ROW, bring that single value back, then, next row, go back and do that again. And again and again.
It's one way to get the data, but it's not usually efficient. Later, though, you'll learn to use correlated sub-queries in (NOT) EXISTS clauses, and in that context they tend to be extremely efficient. Story for another day, but it's one reason the construct is important to know.
So, your way was good, because it was set based and would tend to be more efficient as a sub-query in the FROM clause, but this way, row by row, is important to understand conceptually.
This is how I would do it.
SELECT VendorName, LargestInv.MaxI
FROM Vendors
FROM (
SELECT VendorName, MAX(InvoiceTotal) as MaxI
FROM Invoices
JOIN Vendors ON Invoices.VendorID = Vendors.VendorID
GROUP BY VendorName
) AS LargestInv ON LargestInv.VendorName = Vendors.VendorName
Now having more than one in the sub-query won't give you an error and you can look at the results.
I have this ugly source data with two columns, let's call them EmpID and SomeCode. Generally EmpID maps to the EmployeeListing table. But sometimes, people are entering the Employee IDs in the SomeCode field.
The person previously running this report in Excel 'solved' this problem by performing multiple vlookups with if statements, as well as running some manual checks to ensure results were accurate. As I'm moving these files to Access I am not sure how best to handle this scenario.
Ideally, I'm hoping to tell my queries to do a Left Join on SomeCode if EmpID is null, otherwise Left Join on EmpID
Unfortunately, there's no way for me to force validation or anything of the sort in the source data.
Here's the full SQL query I'm working on:
SELECT DDATransMaster.Fulfillment,
DDATransMaster.ConfirmationNumber,
DDATransMaster.PromotionCode,
DDATransMaster.DirectSellerNumber,
NZ([DDATransMaster]![DirectSellerNumber],[DDATransMaster]![PromotionCode]) AS EmpJoin,
EmployeeLookup.ID AS EmpLookup,
FROM FROM DDATransMaster
LEFT JOIN EmployeeLookup ON NZ([DDATransMaster]![DirectSellerNumber],[DDATransMaster]![PromotionCode]) = EmployeeLookup.[Employee #])
You can create a query like this:
SELECT
IIf(EmpID Is Null, SomeCode, EmpID) AS join_field,
field2,
etc
FROM YourTable
Or if the query will always be used within an Access session, Nz is more concise.
SELECT
Nz(EmpID, SomeCode) AS join_field,
field2,
etc
FROM YourTable
When you join that query to your other table, the Access query designer can represent the join between join_field and some matching field in the other table. If you were to attempt the IIf or Nz as part of the join's ON clause, the query designer can't display the join correctly in Design View --- it could still work, but may not be as convenient if you're new to Access SQL.
See whether this SQL gives you what you want.
SELECT
dda.Fulfillment,
dda.ConfirmationNumber,
dda.PromotionCode,
dda.DirectSellerNumber,
NZ(dda.DirectSellerNumber,dda.PromotionCode) AS EmpJoin,
el.ID AS EmpLookup
FROM
DDATransMaster AS dda
LEFT JOIN EmployeeLookup AS el
ON NZ(dda.DirectSellerNumber,dda.PromotionCode) = el.[Employee #])
But I would use the Nz part in a subquery.
SELECT
sub.Fulfillment,
sub.ConfirmationNumber,
sub.PromotionCode,
sub.DirectSellerNumber,
sub.EmpJoin,
el.ID AS EmpLookup
FROM
(
SELECT
Fulfillment,
ConfirmationNumber,
PromotionCode,
DirectSellerNumber,
NZ(DirectSellerNumber,PromotionCode) AS EmpJoin
FROM DDATransMaster
) AS sub
LEFT JOIN EmployeeLookup AS el
ON sub.EmpJoin = el.[Employee #])
What about:
LEFT JOIN EmployeeListing ON NZ(EmpID, SomeCode)
as your join, nz() uses the second parameter if the first is null, I'm not 100% sure this sort of join works in access. Worth 20 seconds to try though.
Hope it works.
You Could use a Union:
SELECT DDATransMaster.Fulfillment,
DDATransMaster.ConfirmationNumber,
DDATransMaster.PromotionCode,
DDATransMaster.DirectSellerNumber,
EmployeeLookup.ID AS EmpLookup
FROM DDATransMaster
LEFT JOIN EmployeeLookup ON
DDATransMaster.DirectSellerNumber = EmployeeLookup.[Employee #]
where DDATransMaster.DirectSellerNumber IS NOT NULL
Union
SELECT DDATransMaster.Fulfillment,
DDATransMaster.ConfirmationNumber,
DDATransMaster.PromotionCode,
DDATransMaster.DirectSellerNumber,
EmployeeLookup.ID AS EmpLookup
FROM DDATransMaster
LEFT JOIN EmployeeLookup ON
DDATransMaster.PromotionCode = EmployeeLookup.[Employee #]
where DDATransMaster.DirectSellerNumber IS NULL;
This is going to seem like a lame question for all experts in SQL server views but...
So I have a small set of data that my client needs for reporting purposes. I have to admit that although I did ask them their reporting requirements, it isn't till now that I see that my db could be better optimised.
One of the pieces of data they want is the time difference between two tasks that may have run:
select caseid, hy.createdate
from app_history hy
where hy.activityid in (303734, 303724)
This gives me two rows (after edit) per case-submission which then have to be measured; but a few wiggles:
Activity 303734 will always run, activity 303724 might run.
Each 303734 and 303724 combo match up. Conceiveably a case can have 1 un-matched 303734 with a matched pair afterwards on the 2nd submission. Matching these might be down to intuition. Not good.
There maybe more than one submission per caseid and if that is the case then both activities will run every subsequent time.
There is no way to write the submission number to this table.
The app_history table holds userid, caseid and activityid as foreign keys. The PK is the identity column ID.
Is there a better way to write the query?
AFter help from KM:
select
c.id, c.submissionno, hya.caseid, hya.createtime, hyb.caseid, hyb.createtime
,CASE
WHEN hyb.caseid IS NOT NULL THEN DATEDIFF(mi,hya.createtime,hyb.createtime)
ELSE NULL
END AS Difference
from app_case c
inner join app_history hya on c.id = hya.caseid
left outer join app_history hyb on c.id = hyb.caseid
where hya.activityid in (303734) and hyb.activityid in (303724) order by c.id asc
This nearly works.
I now have this issue:
460509|2|460509|15:15:39.000|460509|15:16:13.000|1
460509|2|460509|15:15:39.000|460509|15:18:13.000|3
460509|2|460509|15:17:52.000|460509|15:16:13.000|-1
460509|2|460509|15:17:52.000|460509|15:18:13.000|1
So I am now getting 1 row comparing each of the two for each of the four rows... mmm I think it is the best I can hope for. :(
USE LEFT JOIN
SELECT
a.caseid, a.createdate
,b.caseid, b.createdate
,CASE
WHEN b.caseid IS NOT NULL THEN DATEDIFF(mi,a.createdate,b.createdate)
ELSE NULL
END AS Difference
FROM app_history a
LEFT OUTER JOIN app_history b ON b.activityid=303724
WHERE a.activityid=303734
EDIT after a little more schema info...
SELECT
a.caseid, a.createdate
,b.caseid, b.createdate
,CASE
WHEN b.caseid IS NOT NULL THEN DATEDIFF(mi,a.createdate,b.createdate)
ELSE NULL
END AS Difference
FROM (SELECT MAX(ID) AS MaxID FROM app_history WHERE activityid=303734) aa
INNER JOIN app_history a ON aa.MaxID=a.ID
LEFT OUTER JOIN a(SELECT MAX(ID) AS MaxID FROM app_history WHERE activityid=303724) bb ON 1=1
LEFT OUTER JOIN app_history b ON bb.MaxID=b.ID
do something like this
select datediff(
day,
(select isnull(hy.createdate,0) from app_history hy where hy.activityid =303734),
(select isnull(hy.createdate,0) from app_history hy where hy.activityid =303724)
)