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Update a single row & column in one table with values from a different table's multiple rows and columns

Hello Experts:

This is a hard one.

I have a table called INV that has columns ItemNo, Whse, Locator, QtyOnHand, LastUpdateDate.  There are many records for each ItemNo.
I need to post a consolidated string from INV into BOM, matching on BOM.ItemNo = INV.ItemNo.
I need three rows of three columns each from INV to update 1 row, 1 column in BOM.

Specifically, on each matching ItemNo, I need the first 3 rows from INV, columns "Whse, Locator, QtyOnHand"  consolidated into a single string and posted into BOM.InvDetails.

I tried this:

UPDATE b SET InvDetails =

(select * from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum1 from INV where itemNo = b.ItemNo ) a1 where rnum1 = 1)
+
(select * from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum2 from INV where itemNo = b.ItemNo ) a2 where rnum2 = 2)
+
(select * from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum3 from INV where itemNo = b.ItemNo ) a3 where rnum3 = 3)

FROM BOM b


I GET THIS ERROR: Only one expression can be specified in the select list when the subquery is not introduced with EXISTS.

I know how to do this procedurally using a sequence of queries in a loop but that takes too long and I'm trying to learn how to do this within a single SQL transaction.  So Please, do not send me any examples of using a do/loop or for/each, etc.


If anyone could send a working TSQL example to me, that would be really great!!!

Thanks in advance.


0
LovinSpoonful
Asked:
LovinSpoonful
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1 Solution
 
LovinSpoonfulAuthor Commented:
I am using SQL Server 2008
0
 
ThomasianCommented:
;WITH CTE AS (
	select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails
		, ROW_NUMBER() OVER (PARTITION BY itemNo ORDER BY lastupdatedate) rnum
	from INV
)
UPDATE b
SET InvDetails= (SELECT ISNULL(MAX(invDetails),'') FROM CTE WHERE itemNo=b.itemNo AND rnum=1)
				+(SELECT ISNULL(MAX(invDetails),'') FROM CTE WHERE itemNo=b.itemNo AND rnum=2)
				+(SELECT ISNULL(MAX(invDetails),'') FROM CTE WHERE itemNo=b.itemNo AND rnum=2)
FROM BOM b

Open in new window

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ThomasianCommented:
Correction:

For Line 9: rnum = 2 should be rnum=3
0
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Luan JubicaProject ManagerCommented:
UPDATE b SET InvDetails =

(select invDetails from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum1 from INV where itemNo = b.ItemNo ) a1 where rnum1 = 1)
+
(select invDetails from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum2 from INV where itemNo = b.ItemNo ) a2 where rnum2 = 2)
+
(select invDetails from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum3 from INV where itemNo = b.ItemNo ) a3 where rnum3 = 3)

FROM BOM b
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LowfatspreadCommented:
its because you have select * in your subqueries ... you can only return a single column...

UPDATE b SET InvDetails =

(select invdetails from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum1 from INV where itemNo = b.ItemNo ) a1 where rnum1 = 1)
+
coalesce((select invdetails from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum2 from INV where itemNo = b.ItemNo ) a2 where rnum2 = 2) ,'')
+
coalesce((select invdetails from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum3 from INV where itemNo = b.ItemNo ) a3 where rnum3 = 3) ,'')

FROM BOM b
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LovinSpoonfulAuthor Commented:
Hello Thomasian, I really like the use of a CTE here, it's something I'm trying to understand.  The query you gave me will execute but it assigns the same value to every row in b table.  The "WHERE itemNo=b.itemNo"  isn't working.  I wonder if there is a small tweak to this we could do ?
0
 
ThomasianCommented:
You can read about CTEs in http://msdn.microsoft.com/en-us/library/ms190766.aspx . If there's anything you don't understand, feel free to ask.

I forgot to include the itemNo from the SELECT statement of the CTE.
;WITH CTE AS (
	select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails
		, ROW_NUMBER() OVER (PARTITION BY itemNo ORDER BY lastupdatedate) rnum
		, itemNo
	from INV
)
UPDATE b
SET InvDetails= (SELECT ISNULL(MAX(invDetails),'') FROM CTE WHERE itemNo=b.itemNo AND rnum=1)
			+(SELECT ISNULL(MAX(invDetails),'') FROM CTE WHERE itemNo=b.itemNo AND rnum=2)
			+(SELECT ISNULL(MAX(invDetails),'') FROM CTE WHERE itemNo=b.itemNo AND rnum=2)
FROM BOM b

Open in new window

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LovinSpoonfulAuthor Commented:
Hello Iuani.  I tried your solution next.  The problem is that it returns a null value in any cases where there aren't 3 records available for that item in the INV table.  
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LovinSpoonfulAuthor Commented:
Hello LowfatSpread,  your solution works fine.  Thank you for showing me the Coalesce function.  The only problem is the speed.  It takes 21 seconds to execute in my db.  Trying the update from Thomasian next...
0
 
LovinSpoonfulAuthor Commented:
Hello Thomasian,  your update works perfectly and executes in 2 seconds.  Thanks for showing me how to do this.  What an awesome solution.
0
 
LovinSpoonfulAuthor Commented:
AWESOME!
0
 
LowfatspreadCommented:
coalesce is not causing you any speed degredation...

the query is merely a correction to the initial one you supplied...

the 21 seconds is you basic database performance "problem"


how have you tested that your selected solution actually performs significantly better...
did you clear cache , etc...

or are you benefiting from the buffers now being populated with the data already retrieved.


good luck
0
 
Luan JubicaProject ManagerCommented:
ISNULL will do the trick :

UPDATE b SET InvDetails =

(select isNULL(invDetails,'') from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum1 from INV where itemNo = b.ItemNo ) a1 where rnum1 = 1)
+
(select isNULL(invDetails,'') from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum2 from INV where itemNo = b.ItemNo ) a2 where rnum2 = 2)
+
(select isNULL(invDetails,'') from (select ' ' + Whse + '.' + rtrim(Locator) + '=' + convert(varchar,QtyOnhand) AS invDetails,
ROW_NUMBER() OVER (ORDER BY lastupdatedate) rnum3 from INV where itemNo = b.ItemNo ) a3 where rnum3 = 3)

FROM BOM b

But I see you already choosed a solution...good luck.



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LowfatspreadCommented:
@luani

the isnull / coalesce needs to cover the whole subquery not be within it

coalesce((subquery),'')
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Luan JubicaProject ManagerCommented:
@Lowfatspread :

I think in his case both will work...but you are right it is better to cover the whole subquery


0
 
LovinSpoonfulAuthor Commented:
For anyone using this solution, for the CTE solution,  don't forget to correct line 9 to say "3" not "2".
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