Performance Related Doubt On The Following Items --&&> LEFT/INNER JOIN Vs IN And Cost Of CONVERT
May 28, 2008
Hi,
1.
Right now in my queries I am using lots of LEFT Joins and INNER JOINs... and I was suggested to look at 'IN'... But with IN I did face some performance issues previously and stopped using it... but I have got new doubts on which query will give me better performance...
A query using LEFTJoin or a query using IN/NOT-IN
2.
This question is about CONVERT...
I have a stored proc which is used for updating a table... and multiple columns [of the same table] and corresponding values are sent to the proc [only a subset of the columns might be sent for updates everytime and the columns to update is not fixed for each run of the SP]...
I have to construct a UPDATE String out of it using string concatenation to finally be able to use "sys.sp_executesql" on that update statement...
This results in me having to use CONVERT() lots of times... and one of the columns among them on which I am doing a CONVERT is of the type XML...
So the question is as follows...
a. Is it preferrable to construct a single UPDATE statement string and execute it using "sys.sp_executesql"
b. Or Is it preferrable to give multiple UPDATE statments... i.e. one update statement for each column [Depending on whether that column has to be updated for that run or not]
i.e. The question essentially is:
Does a single update query constructed using lots of CONVERTS [Basically on INT and XML types]
give more performance over using multiple UPDATE statments on the table
Or is it the other way round..
I am developing reporting service and using lots of 'LEFT OUTER JOIN',I am worried about the performance and want to use some subquery toimprovethe performance.Could I do that like below,[the origin source]SELECT *FROM TableALEFT OUTER JOIN TableBON TableA.item1 = TableB.item1WHERE TableA.item2 = 'xxxx'TableB.item2 > yyyy AND TableB.item2 < zzzzI add the subquery to query every table before 'LEFT JOIN'--------------------------------------------------------------------------SELECT *FROM(SELECT *FROM TableAWHERE TableA.item2 = 'xxxx') TableCLEFT OUTER JOIN(SELECT *FROM TableBWHERE TableB.item2 > yyyy AND TableB.item2 < zzzz) TableDON TableC.item1 = TableD.item1WHERE TableC.item2 = 'xxxx'TableD.item2 > yyyy AND TableD.item2 < zzzz--------------------------------------------------------------------------Can anyone give me some suggestion?Thanks a lot.Leland Huang
SELECT * FROM a LEFT OUTER JOIN b ON a.id = b.id instead of
SELECT * FROM a LEFT JOIN b ON a.id = b.id
generates a different execution plan?
My query is more complex, but when I change "LEFT OUTER JOIN" to "LEFT JOIN" I get a different execution plan, which is absolutely baffling me! Especially considering everything I know and was able to research essentially said the "OUTER" is implied in "LEFT JOIN".
I was thinking last night of restructuring the way "Related Items" are pulled from the database for one of our sites. Basically at the moment it is upto the client to flag two products as related. I'm thinking of using a new method of tagging the products and then finding related products based on the tags assigned -the general code for this is below but what I want to know is, is using "IN" the most efficient way of doing this?
TIA
Tim
DECLARE @ItemId int SET @ItemId = 1
SELECT COUNT(i.ItemId) AS MatchingTags, i.ItemId, i.ItemName FROM tst_Items i LEFT JOIN txt_x_Items_Tags x ON i.ItemId = x.ItemId WHERE x.TagId IN ( SELECT t.TagId FROM tst_Tags t LEFT JOIN txt_x_Items_Tags x ON t.TagId = x.TagId WHERE x.ItemId = @ItemId ) GROUP BY i.ItemId, i.ItemName HAVING i.ItemId <> @ItemId ORDER BY MatchingTags DESC
The testing data:
CREATE TABLE [dbo].[tst_Items]( [ItemId] [int] NOT NULL, [ItemName] [nvarchar](50) NOT NULL ) ON [PRIMARY] GO CREATE TABLE [dbo].[tst_Tags]( [TagId] [int] NOT NULL, [TagName] [nvarchar](50) NOT NULL ) ON [PRIMARY] GO CREATE TABLE [dbo].[txt_x_Items_Tags]( [ItemId] [int] NOT NULL, [TagId] [int] NOT NULL ) ON [PRIMARY] GO INSERT INTO tst_Items VALUES (1, 'Test Item 1') INSERT INTO tst_Items VALUES (2, 'Test Item 2') INSERT INTO tst_Items VALUES (3, 'Test Item 3') INSERT INTO tst_Items VALUES (4, 'Test Item 4')
INSERT INTO tst_Tags VALUES (1, 'Tag 1') INSERT INTO tst_Tags VALUES (2, 'Tag 2') INSERT INTO tst_Tags VALUES (3, 'Tag 3') INSERT INTO tst_Tags VALUES (4, 'Tag 4')
INSERT INTO txt_x_Items_Tags VALUES (1, 1) INSERT INTO txt_x_Items_Tags VALUES (1, 2) INSERT INTO txt_x_Items_Tags VALUES (1, 3) INSERT INTO txt_x_Items_Tags VALUES (2, 1) INSERT INTO txt_x_Items_Tags VALUES (2, 3) INSERT INTO txt_x_Items_Tags VALUES (3, 1) INSERT INTO txt_x_Items_Tags VALUES (3, 2) INSERT INTO txt_x_Items_Tags VALUES (1, 4) INSERT INTO txt_x_Items_Tags VALUES (4, 4) GO
---------------------------- I've finally started blogging (all be it badly!)
Check it out: http://blogs.thesitedoctor.co.uk/tim/
Hey guys, I have created an asp.net page where users can select multiple items and then submit the form. I would like to return related items back. The catch is, I want to only return items that are related to all of the selected items. I've created a SQL Procedure that puts each of the inputted item's ItemId in to a temp table, I have a second table called RelatedItems which I use as my junction table that has ItemId, and ReleatedItemId, I then have my Item table that has the data I want to get to (I've excluded this because I have no trouble pulling out data once I have an ItemId) I can pull out all related ItemIds with a simple join, however I don't know where to start when it comes to pulling out only items related to all ItemIds in the @TempTable. Any help or suggestions would be great. Thanks, Matt
I've a table similar to the one below, with a SKU, Category and Cost, and need using a simple select command, split the cost in two columns one for each category (1,2), I used a self-join, and it works, but it doesn't show values not equal in both categories
Declare @Tmp_SKUCatValue Table( SKU char(7) ,Cetegory Int ,Unit_cost Decimal ); INSERT INTO @Tmp_SKUCatValue (SKU, Cetegory,Unit_cost) Values ('sku-001',1,120)
I was writing a query using both left outer join and inner join. And the query was ....
SELECT S.companyname AS supplier, S.country,P.productid, P.productname, P.unitprice,C.categoryname FROM Production.Suppliers AS S LEFT OUTER JOIN (Production.Products AS P INNER JOIN Production.Categories AS C
[code]....
However ,the result that i got was correct.But when i did the same query using the left outer join in both the cases
i.e..
SELECT S.companyname AS supplier, S.country,P.productid, P.productname, P.unitprice,C.categoryname FROM Production.Suppliers AS S LEFT OUTER JOIN (Production.Products AS P LEFT OUTER JOIN Production.Categories AS C ON C.categoryid = P.categoryid) ON S.supplierid = P.supplierid WHERE S.country = N'Japan';
The result i got was same,i.e
supplier country productid productname unitprice categorynameSupplier QOVFD Japan 9 Product AOZBW 97.00 Meat/PoultrySupplier QOVFD Japan 10 Product YHXGE 31.00 SeafoodSupplier QOVFD Japan 74 Product BKAZJ 10.00 ProduceSupplier QWUSF Japan 13 Product POXFU 6.00 SeafoodSupplier QWUSF Japan 14 Product PWCJB 23.25 ProduceSupplier QWUSF Japan 15 Product KSZOI 15.50 CondimentsSupplier XYZ Japan NULL NULL NULL NULLSupplier XYZ Japan NULL NULL NULL NULL
and this time also i got the same result.My question is that is there any specific reason to use inner join when join the third table and not the left outer join.
Select memberfrom NameListInner join Memberson (Left(Namelist.NameID,5) = Members.IDOR (left(namelist.SSN,9) = Members.ssnOR (Left(namelist.CustID,9) + '*01' = Members.CustID)wherenamelist.name <> ''How do I speed up a process like this? Can I create indexes on themembers table based on a functionLike an index based on the left(members.id,5)or should these statements go into the where clause?
OLEDB source 1 SELECT ... ,[MANUAL DCD ID] <-- this column set to sort order = 1 ... FROM [dbo].[XLSDCI] ORDER BY [MANUAL DCD ID] ASC
OLEDB source 2 SELECT ... ,[Bo Tkt Num] <-- this column set to sort order = 1 ... FROM ....[dbo].[FFFenics] ORDER BY [Bo Tkt Num] ASC
These two tasks are followed immediately by a MERGE JOIN
All columns in source1 are ticked, all column in source2 are ticked, join key is shown above. join type is left outer join (source 1 -> source 2)
result of source1 (..dcd column) ... 4-400-8000119 4-400-8000120 4-400-8000121 4-400-8000122 <--row not joining 4-400-8000123 4-400-8000124 ...
result of source2 (..tkt num column) ... 4-400-1000118 4-400-1000119 4-400-1000120 4-400-1000121 4-400-1000122 <--row not joining 4-400-1000123 4-400-1000124 4-400-1000125 ...
All other rows are joining as expected. Why is it failing for this one row?
Why would I use a left join instead of a inner join when the columns entered within the SELECT command determine what is displayed from the query results?
Product Type - A Product Name - 1 Product Price - 1 Product Name - 2 Product Price - 2
Product Type - B Product Name - 1.1 Product Price - 1.1 Product Name - 2.1 Product Price - 2.1 Product Name - 3.1 Product Price - 3.1
Similarly i have different Product types and product names and its prices underneath each product type. As you can see, there might be varied number of products under the product type so i am grouping it on Product type. The issue is when i export the report to pdf or word, when ever we have a big group of Product Type( example: Product Type X and it has 10 different Products under it) along with few other smaller groups, the big group tends to jump on to the next page of word or pdf and leaves a big empty space in the previous page. Any way i can break those big groups and fit as many as we can on the page and the rest should follow onto the next page rather than leaving the previous page with blank space.
Why does this right join return the same results as using a left (or even a full join)?There are 470 records in Account, and there are 1611 records in Contact. But any join returns 793 records.
select Contact.firstname, Contact.lastname, Account.[Account Name] from Contact right join Account on Contact.[Account Name] = Account.[Account Name] where Contact.[Account Name] = Account.[Account Name]
I need to build TSQL query to return the Last unit Cost from my table of movement of goods SL (on CTE) but the MAX(Datalc) must be Less or Equal to my HeaderInvoice.
This is my script:
With MaxDates as ( SELECT ref, MAX(epcpond)[Unitcostprice], MAX(datalc) MaxDate FROM sl
[code]....
the problem I have right now is that the Unitcostprice of my table of goods movements has a top date greather than the date of my bill.
Example:
invoice date : 29.01.2015 unitcost on invoice line = 13,599722 Maxdate (CTE) : 19.03.2015 unitCost from my table of movement of goods = 14,075
That ´s not correct because the MAxdates > invoice date and the unitCost of 14,075 is the cost on 19.03.2015 and not just before my invoice date.
I right in thinking that if the estimated subtree cost is higher than the cost threshold for parallelism then it will use a parallel plan? If so, I've read the cost threshold is measured in minutes but is the subtree cost measured in something else, the mysterious cost number? And if so, how are the two compared?
We have SQL Server 7.0 running on a NT 4 sp6 server and non of its items track in performance monitor. Under the SQL program tab, when performance monitor is clicked, it comes up and has items for SQL, but they all track as zero. You can "add" other items such as processor items and they track fine. Any ideas???
Thanks in advance!
Ray Peterson EPA Seattle 206-553-1682 peterson.ray@epa.gov
I'm trying to join 2 tables. I thought I was getting the correct results but it turns out I'm not. My Query: SELECT IVINVA, IVORDN, IVCSLN, IVRESR, IVCITM, CONVERT(varchar(12),CAST(IVIAMT as money),1) AS ExtPrice, CONVERT(varchar(12),CAST(IVPIVC as money),1) AS DistPrice, IVCSUM, IVQYCS, IVDESC, OIRESR, OIDPCT, CONVERT(varchar(12),CAST(IVPIVC - (OIDPCT / 100 * IVPIVC) as money),1) AS NetPrice FROM INVDET1_TBL LEFT JOIN ORDDIS_TBL ON ORDDIS_TBL.OIORDN = INVDET1_TBL.IVORDN AND ORDDIS_TBL.OIRESR = INVDET1_TBL.IVRESR WHERE IVORDN = '0859919' AND IVINVA = '00324024' Basically, my problem lies in the seonc condition of the LEFT JOIN. I needed to set the two tables equal my item number, because in some situations I need that logic to get the correct result. It most other cases, that item column in the ORDDIS_TBL is NULL, thus giving me the wrong results. In that case, I would want the JOIN to only be ORDDIS_TBL.OIORDN = INVDET1_TBL.IVORDN, and not include the second part. Is there a way I can condition this with an If statement, If ORDDIS_TBL.OIRESR is Null then do this join, if not, then do this? I'm confused how to get the proper result here.
3) select p.komorka,isnull(sum(ustalenia),0) from #plantemp p left join analiza_1 a on p.komorka=a.komorka where a.koniec between '20040701'and '20040731' group by p.komorka
komorka ustalenia (sum)
08.0000 SI/1788138.9300 SI/262856.8900
I need all rows from table 1 bat right and left join gives me the same results, WHY
As you can see the ParentIndexID and ChildIndexID fields refer to tblIndices.IndexID I would like a stored procedure as follows: show all index names and show the wights for the indexID you passed. This is what I have so far and it is not correct yet. Not sure what the syntax should be.
alter PROCEDURE [dbo].[uspBasketIndices_Get]
@IndexIDint
AS
select i.IndexID, i.[Name], bc.Weight from tblIndices as i left join tblBasketConstituents as bc on i.IndexID = bc.ParentIndexID and i.IndexID = @IndexID order by i.[Name]
Any one know any facts and figures about maximum Left Joins allowed (or recommended) in one query?
I am running a MS SQL 2000 my database is full of relational data and most of my foreign keys (INT data type) are a Clustered Indexed, Usually I will only be pulling one record from collection of about a dozen tables, but the Database is expected to grow fast and become big.
Right now I have a Stored Proc that has eight(8) LEFT JOINs in it. My worry is that this query will kill me as the database approaches 50,000 records.
Hi all. My query works fine, it generates reports but not my expected result.
select d.fullname, p.nickname, p.birthdate, p.birthplace, p.gender, p.civilstatus, p.religion, p.nationality, p. weight, p.height, p.haircolor, p.eyecolor, p.complexion, p.bodybuilt, p.picture, p.dialectspoken, d.mobilephone, d.prprovince,[Age] = dbo.F_AGE_IN_YEARS( birthdate, getdate() ), c.name, c.address, c.telno, c.email, c.occupation, ed.year1, ed.year2, ed.degree, sch.schname from hremployees as e inner join psdatacenter as d on e.empdcno = d.dcno inner join pspersonaldata as p on e.empdcno = p.dcno left join hrappempcharrefs as c on e.empdcno = c.empdcno left join hrappempeducs as ed on e.empdcno = ed.empdcno left join hrsetschools as sch on ed.schoolcode = sch.schcode
the above query gives a 77 records
if i ran "select * from hremployees" generates 60 records
i think the error is in the left joining. hrappempcharrefs, hrappempeducs and hrsetschools must be left joined to hremployees.
Hi Group,My apologies for the lengthy post, but here goes...I have the following tables:TABLE Vehicles([ID] nvarchar(5),[Make] nvarchar(20),[Model] nvarchar(20),)TABLE [Vehicle Status]([ID] int, /* this is an auto-incrementing field*/[Vehicle ID] nvarchar(5), /* foriegn key, references Vehicles.[ID] */[Status] nvarchar(20),[Status Date] datetime)Here's my problem...I have the following data in my [Vehicles] and [Vehicle Status] tables:[ID] [Make] [Model]----------------------H80 Nissan SkylineH86 Toyota Aristo[ID] [Vehicle ID] [Status] [Status Date]----------------------------------------1 H80 OK 2006-10-012 H80 Damage 2006-10-053 H86 OK 2006-10-134 H86 Dent 2006-10-155 H86 Scratched 2006-10-16I need a query that will join the two tables so that the most recentstatus of each vehicle can be determined. I've gotten as far as:SELECT Vehicle.[ID], Make, Model, [Status], [Status Date] FROM[Vehicles] INNER JOIN [Vehicle Status] ON [Vehicles].[ID] = [VehicleStatus].[Vehicle ID]Of course this produces the following results:[ID] [Make] [Model] [Status] [Status Date]--------------------------------------------H80 Nissan Skyline OK 2006-10-01H80 Nissan Skyline Damage 2006-10-05H86 Toyota Aristo OK 2006-10-13H86 Toyota Aristo Dent 2006-10-15H86 Toyota Aristo Scratched 2006-10-16How do I filter these results so that I get only the MOST RECENT vehiclestatus?i.e:[ID] [Make] [Model] [Status] [Status Date]--------------------------------------------H80 Nissan Skyline Damage 2006-10-05H86 Toyota Aristo Scratched 2006-10-16Thanks in advance,Rommel the iCeMAn*** Sent via Developersdex http://www.developersdex.com ***
I have a table of products, and many products have the same name only they are different sizes. I want to only select a particular size like 20 oz, but if it does not exist in that size I want to select the next appropriate size (and which case if it does not exist i wish to select the next appropriate size and so on .. Does any one know how I can accomplish this and would be willing to help me out by posting some code, some direction ??
Other than being much less readable, is there a downside to combining left and right outer joins in the same SELECT? I'm reviewing some generally poor code done by a contractor and it's peppered with queries with both left and right joins. I've always thought it was just a semantic difference, but I was just wondering if, other than readability, there were any performance issues.
Hi Guys, I started working with linq and vb9.0 but i have a small problem i could feagure how to solve in c# but not in vb I wanted to make left join or right join on vb 9.0 and linq is it possible or this is only c# feature ? Waiting to hear from u guys, Thanks Softy
