Hi all,
Recently saw some posts about how bad it is using subqueries (nested queries) and things like all the queries can be written with JOIN instead. However, for a query like the followings, I cannot figure out how to do it properly.
The data looks like the following, it contains 3 columns, id, which is the primary key of the table (unique), group, as which group this entry belongs to, and the article type, where 0 is not an article.
What the query is trying to achieve is for each group, get the latest (maximum) id, and the article type (bear in mind "0" is not one of the allowed type). so for data above, the result will look something like this...
id grp article
5 1 2
9 2 1
18 3 1
The following is the query I come up with, the problem is, I don't know how to get the same result without using subquery. I don't even see how it is possible. Guys, please share some light with me, and educate me on this.
select a.id, a.grp, b.article
from
(
SELECT max(id) as id, grp
from list a
where article != 0
group by grp
) a
join list b
on a.id = b.id
I read that merge joins work a lot faster than hash joins. How would you convert a hash join into a merge join? (Referring to output on Execution Plan diagrams.) THANKS
I have a SQL query where am using WHERE clause as a result of which the NULL values are getting filtered...can u please help me to tranform this query into LEFT OUTER JOINS so as to avoid this filtration....my query is
SELECT A.JOINT_ID,A.SIZE_NBMM,A.ISFIELDJOINT,A.WELDTEST_CRI_ID,C.LINE_ID,D.TESTLEVELNO,E.COMPLETE FROM EALPS_DRWREVSPLJTS
A,EALPS_DRW_REV_SPL B,EALPS_DRW_REV_LINE C,EALPS_WELDTESTCRIT D,EALPS_ACTV_SEQ E WHERE B.SPOOL_ID=A.SPOOL_ID AND
B.LINE_ID=C.LINE_ID AND D.WELD_TEST_CRIT_ID=A.WELDTEST_CRI_ID AND E.ACTIVITY_CODE='VT' AND E.JOINT_ID=A.JOINT_ID
I am using this sql script to achieve paging functionality for a site. IT works great for the most part, except when I need to return a result set that includes other tables.
How can I add another parameter to this to allow joined table to be a paramter? I'd like to pass in the join table name and columns to join on, or a custom select statement I guess?
CREATE PROCEDURE GetSortedPage( @TableName VARCHAR(50), @PrimaryKey VARCHAR(25), @SortField VARCHAR(100), @PageSize INT, @PageIndex INT = 1, @QueryFilter VARCHAR(100) = NULL ) AS SET NOCOUNT ON
DECLARE @SizeString AS VARCHAR(5) DECLARE @PrevString AS VARCHAR(5)
SET @SizeString = CONVERT(VARCHAR, @PageSize) SET @PrevString = CONVERT(VARCHAR, @PageSize * (@PageIndex - 1))
IF @QueryFilter IS NULL OR @QueryFilter = '' BEGIN
EXEC( 'SELECT * FROM ' + @TableName + ' WHERE ' + @PrimaryKey + ' IN (SELECT TOP ' + @SizeString + ' ' + @PrimaryKey + ' FROM ' + @TableName + ' WHERE ' + @PrimaryKey + ' NOT IN (SELECT TOP ' + @PrevString + ' ' + @PrimaryKey + ' FROM ' + @TableName + ' ORDER BY ' + @SortField + ') ORDER BY ' + @SortField + ') ORDER BY ' + @SortField ) EXEC('SELECT (COUNT(*) - 1)/' + @SizeString + ' + 1 AS PageCount FROM ' + @TableName)
END ELSE BEGIN
EXEC( 'SELECT * FROM ' + @TableName + ' WHERE ' + @PrimaryKey + ' IN (SELECT TOP ' + @SizeString + ' ' + @PrimaryKey + ' FROM ' + @TableName + ' WHERE ' + @QueryFilter + ' AND ' + @PrimaryKey + ' NOT IN (SELECT TOP ' + @PrevString + ' ' + @PrimaryKey + ' FROM ' + @TableName + ' WHERE ' + @QueryFilter + ' ORDER BY ' + @SortField + ') ORDER BY ' + @SortField + ') ORDER BY ' + @SortField ) EXEC('SELECT (COUNT(*) - 1)/' + @SizeString + ' + 1 AS PageCount FROM ' + @TableName + ' WHERE ' + @QueryFilter)
Hi... I have 3 tables:SportTeams (TeamID, TeamName)SportAthletes (TeamID, AthleteID, AthleteName)SportMedals (AthleteID, Medal) I want to have a brief medal list (TeamID, G, S, B). I can write query in systax: Select a.TeamID, a.TeamName_en,g.G,s.S,b.B from SportTeams aLeft Join(Select c.TeamID,Count(*) as G from SportMedals b Inner Join SportAthletes c On b.AthleteID = c.AthleteIDWhere Medal = 'G'Group By c.TeamID) g On a.TeamID = g.TeamIDLeft Join(Select c.TeamID,Count(*) as S from SportMedals b Inner Join SportAthletes c On b.AthleteID = c.AthleteIDWhere Medal = 'S'Group By c.TeamID) s On a.TeamID = s.TeamIDLeft Join(Select c.TeamID,Count(*) as B from SportMedals d Inner Join SportAthletes c On d.AthleteID = c.AthleteIDWhere Medal = 'B'Group By c.TeamID) b On a.TeamID = b.TeamIDOrder By g.G desc, s.S desc, b.B desc, a.TeamID asc But I can't write it in LINQ syntax (I am beginner with C#, LINQ) Can you help this sample to LINQ systax? Thanks!
I am wanting to get the job name based on sys.sysProcesses.[Program_name] column. Why is this query not returning any results even though the 2nd substringed guids are found the the sysJobs table?
SELECTCASE WHEN RTRIM([program_name]) LIKE 'SQLAgent - TSQL JobStep (Job %' THEN J.Name ELSE RTRIM([program_name]) END ProgramName , Val1.UqID , Val1.UqIDStr
I am using stored procedure to load gridview,i want to show row specific values in coloumns , as i an working on daily timetable of college and There are three tables Week_Day,Daily_Timetable & Subject.Daily_Timetable has data which has week_day,class_id,Subject_id,Period_No.
Each day has 6 periods and each period is mapped with subject in daily timetable.From below sql i am getting 6 rows of monday.
But i want to show in a row weekname,period1_subject_id(Period_No=1),period2_subject_id(Period_No=2),period3_subject_id.......upto period6_subject_id.
Please see my query below:-
SELECT Week_Day.Week_Day_name, Subject.Subject_Code, Daily_Timetable.Period_No FROM Week_Day LEFT JOIN Daily_Timetable ON Week_Day.Week_Day_Id = Daily_Timetable.Week_Day_Id and Daily_Timetable.Class_Id=6 LEFT JOIN Subject ON Daily_Timetable.Subject_Id = Subject.Subject_Id order by Week_Day.Week_Day_Id ,Daily_Timetable.Period_No
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..
A question for everyone: With the introduction of SQL 2005, we now have to use ANSI-92 T-SQL Syntax and I was wondering if anyone had written a tool to convert queries from old ANSI SQL to the new syntax.
We have some code that has to change for the outer joins, but we also have a lot of code that should change for the inner joins. It doesn't seem that difficult to write something that parses an old piece of code and at least suggests a new version. Especially if the conversion code wasn't SQL code.
Table #1 SELECT EID, DATEPART(wk,[Date]) AS Week, MAX([Date]) AS WeekEnding FROM Employee_Hours WHERE ([Date] Between '1/1/04' AND '12/31/04') GROUP BY EID, DATEPART(wk,[Date]) HAVING MAX([Date]) = '1/24/04' --Pay period
Table #2 SELECT EID, DisplayName FROM Employee WHERE (Active=1)
I tried subqueries and temp tables but can't get the results I need. The first query will return the employees who entered their time for the given pay period.
I have the following sql statement: INSERT INTO prg_lvl VALUES ( 'Data Recovery', 'Data Recovery', 7, 'ENG', 0, 16, 'Menu=w_data_recovery_stk;', ( select max(menu_id) + 1 from prg_lvl ), 'K'); that works for Sybase and I wanna make it works for SQL Server.
The problem is the use ot the subquery (select max(menu_id) + 1 from prg_lvl).
Could I use subqueries in SQL Server in general or is there is any other method to overcome this problem
I am very new to SQL Server, working with it in class. I am trying to do procedures involving subqueries using the Northwind database, and am having a rough time.
For instance, I have the following code, which lists all orders for the month of November, 1996:
SELECT Customers.CustomerID, Customers.CompanyName, CAST(Orders.OrderDate AS CHAR (11) )AS OrderDate FROM Customers, Orders WHERE Customers.CustomerID = Orders.CustomerID AND OrderDate BETWEEN '11/1/1996' AND '11/30/1996' ;
I have been asked to do the same thing, but using a subquery. I came up with the following:
SELECT CustomerID, CompanyName FROM Customers a WHERE EXISTS (SELECT OrderDate FROM Orders b WHERE a.CustomerID = b.CustomerID AND OrderDate BETWEEN '11/1/1996' AND '11/30/1996' ) ;
However, it does not list the Order Date, as I want it to, and the information is not correct (it is missing a few orders from November '97 that should show up. Can someone tell me what I am doing incorrectly?
Please note that I do not need anyone to give me the code, but simply give me an idea of what I am doing incorrectly, or let me know how it can be done, so that I may do it. =-)
Hi all,I've seen mention that you can use nested subqueries down to as manylevels as you like but whenever I run the following:select * from table1where tab1ID in(select tab1ID from table2 where tab2ID in(select tab2ID from Table3 where Tab3ID=N))I get the error "incorrect syntax near the keyword 'where'"Can anyone confirm that sub-subqueries are possible? If so is thesyntax I'm using correct?I'm running SQL 2000 through a Delphi 5 app.RegardsJon
Guys,Got this query...---------------------------SELECT TOP 5 Tbl_admin_hotels.HotelName,(SELECT COUNT(Tbl_marketing_history.HotelID)FROM Tbl_marketing_historyWHERE Tbl_marketing_history.HotelID = Tbl_admin_hotels.HotelID)AS CountTotal,(SELECT MAX(DateSent)FROM Tbl_marketing_historyWHERE Tbl_marketing_history.HotelID = Tbl_admin_hotels.HotelID)AS LastSentFROM Tbl_admin_hotelsWHERE NOT Tbl_admin_hotels.HotelID = 99ORDER BY CountTotal DESC---------------------------Within the table Tbl_marketing_history there is also a 'Subject' column thatI require, the row to grab this Subject column from should relate to the rowI'm selecting in the SubQuery to grab 'DateSent'.I've tried and tried to grab multiple columns but failed miserably? Cananyone help pleaseeee!Cheers, Ash
In this stored procedure, I want to grab all the information for Sales Representatives that made less then 6 visits. I have done that in the subquery. But I also want to be able to display their visits by Dates where any number of visits was made. Meaning, i want to be able to show Everyday where a visit was made, but i only want the records that are less then 6 visits. So I want nulls to show up for the dates where no visits were made. So I can track the people that didnt make visits, on days other made visits (which means they should have visits too)
So basically my report looks like this: 09-10-2007 09-11-2007 09-14-2007 Tom Smith 1 3 4 Janice Cooper 3 5 5 Troy Slater 5 4 2 Kelly Short 4 4 4
When i want it to look like this:
09-10-2007 09-11-2007 09-12-2007 09-13-2007 09-14-2007 Tom Smith 1 3 null null 4 Janice Cooper 3 5 null null 5 Troy Slater 5 4 null null 2 Kelly Short 4 4 null null 4
Its an exception report, so i want to show what was not done , on days that are supposed to have things done, i cant show this, if dates are not displayed before there were no visits less then 6. I want to display all relevant dates, where any number of visits was mad. But only show the visits that were less then 6.
Here's my stored procedure that already has the less then 6 visits showing. But doesnt always show the dates. What should i do?
Hey everyone, I'm running into an issue where I have a select statement that retrieves all employee records from a employee table. In this statement I'm displaying first and last name, titlte and the employees manager id(which is the employees id). What I want is a query that instead of displaying the manager's id, display the manager's name. The query that I'm using below doesn't work. I was hoping that someone could help me out: SELECT LastName, FirstName, Title, Extension, (SELECT FirstName, LastName FROM Employees WHERE (ReportsTo = EmployeeID)) AS Reports FROM Employees
Here's the data that I'm using: LastName, First Name Title Extension Reprots To
Davolio Nancy Sales Representative 5467 13
Fuller Andrew Vice President, Sales 3457 0
Leverling Janet Sales Representative 3355 12
When I run this query I get a error saying "Only one expression can be specified in the select list when the subquery is not introduced with Exists"
So I already no this can't be done... but I need a suitable alternative (if one exists) so I don't have to competely re-write this already too huge query. Anyways, in my select I have something like this: sum( case when code in (1,2,3,4) then 0 else 1 end ) as total which has now increase from four static values to a more dynamic format, that being a table with 47 values which may shrink or grow over time. Attempting the following fails: sum( case when code in (select code_id from ExcludedCodes) then 0 else 1 end ) as total because apparently you can't use selects or aggregates within an aggregate. So any ideas on how I can get this working... is there no Array or List type variable I could just substitute in? I've already tried using a Table Variable, but that failed as well. Please keep in mind, this is one line of a very large select containing many other fields and aggregates (on a fair amount of joins) which is used in at least four differerent reporting queries. If there is no quick and easy replacement trick I can do just let me know so I can start re-writing all of them (which is seriously going to make my head hurt).
Hi, I have searched through this forum and haven't found the answer to a problem I am having so I figured I will post it.
My SQL statement:
Select * FROM tblData WHERE LastName= (SELECT tblData.LastName FROM tblData GROUP BY tblData.LastName HAVING (Count(tblData.LastName)>1))"
What I am trying to do: I am trying to make an SQL filter that I can apply to my form in order to only show records with duplicate last names. The sub query returns names that are already in the table. I then compare what is found to be duplicate with the original table in order to just show only the duplicate records. Everything works fine as long as there is only one name thats duplicated.
When there are multiple duplicate names then I run into an error.
When the statement is put into a string and executed in VBA I get this error:
"Run-time error '3021': No current record."
When the statement is put into a query and run against the DB I get this error:
"At most one record can be returned by this subquery"
So yeah, any help would be greatly appreciated. Am I going about this all wrong or am I just forgetting something? Thanks for any help.
I would like to know which of the following query is the fastest:
select * from customers C where exists (select 0 from ORDERS O where C.Name like 'A%' and O.Charged = 1)
select * from customers C where exists (select 0 from ORDERS O where O.Charged = 1) and C.Name like 'A%'
I don't want to use a JOIN clause. I just want to know if there is a difference of efficiency when the condition on C.Name is inside or outside the sub query.
I would like to know which of the following query is the fastest:
select * from customers C where exists (select 0 from ORDERS O where C.Name like 'A%' and O.Charged = 1 and O.Customers_Id = C.Id)
select * from customers C where exists (select 0 from ORDERS O where O.Charged = 1 and O.Customers_Id = C.Id) and C.Name like 'A%'
Because the condition C.Name like 'A%' is inside the sub query, I'm wondering if it will be evaluated for each record of the Orders table. Does anyone know if there is a difference of efficiency when this condition is inside or outside the sub query ?
I have tried this insert comand and it errors out telling me that icannot use subqueries this way. INSERT INTO tblPartLocation(PartLocation, Part)VALUES (999,(SELECT PartID FROM tblParts WHEREPartName = 'test'))how would i insert a value from a query?thanks for any help
I need to build a view that has 4+ columns that are "counts" of relationships with other tables.
for example:
Code Snippet select Name, Description, (select count(*) from PetOwner PO where PO.OwnerId = O.Id) as PetCount from O Owner
I need to add a few more counts to this query, but I'm thinking that is a bad idea since the number of joins is going to get out of control if I need more counts.
I've created a view with all the counts and it works fine.
I want to index the view so the counts aren't calculated everytime the query is run, but I can't index if I use a subquery like this.
In the end I want the result set to have these columns.
I have a table with two columns: OID and Cumulative (witch is the same type as OID) Each OID can have one or more Cumulatives.
Example of data: OID Cumulative 167 292 167 294 167 296 168 292 169 302 169 304
The cumulation of each OID don't stop at one cumulation, but can be endless (theoretical). Example: 167->292->590 So the table would have on more row: OID Cumulative 295 505
I would like to represent this strucuture in a tree view and I'm looking for a query that could give me a table with this structure: OID Cumul1 Cumul2 Cuml3 Cuml4 .... Cumuln in the way I can read the row and have as many child nodes as I have values in the columns. The number of columns depends on the row with most cumulations.
How can I do the query? Is there a better way as my table with n columns?
I've been using this syntax for years on SQL Server and now comes the time to convert to SQL 2005 (90 compatibility). This syntax returns four rows. Basically it returns one row for each servername/component/context/property/value even when there does not exist a property of 'fff' since it's a left join:
Code Block select t1.* from tblconfiguration t1 ,tblconfiguration t2 where t1.component = 'AdjProcessUtility' and t1.servername *= t2.servername and t1.component *= t2.component and t1.context *= t2.context and t1.property = 'proc' and t2.property = 'fff'
When the converted (using SQL enterprise Mgr) runs it returns no rows:
Code Block SELECT t1.* FROM dbo.tblConfiguration t1 LEFT OUTER JOIN dbo.tblConfiguration t2 ON t1.ServerName = t2.ServerName AND t1.Component = t2.Component AND t1.Context = t2.Context WHERE (t1.Component = 'AdjProcessUtility') AND (t1.Property = 'proc') AND (t2.Property = 'fff')
I don't really see how to change this query to make it work. I've searched the web and I really don't see any examples of left joins which use more than one column.
Here's the table definition:
Code Block CREATE TABLE dbo.tblConfiguration ( ServerName VARCHAR(30) NOT NULL, Component VARCHAR(255) NOT NULL, Context VARCHAR(255) NOT NULL, Property VARCHAR(255) NOT NULL, CONSTRAINT PK_tblConfiguration PRIMARY KEY NONCLUSTERED( ServerName, Component, Context, Property ), Value VARCHAR(255) NOT NULL )
I use this table to define reports and there attribues. The rows repeat themselves except for the Property and Value columns Here is some of the data:
Dear experts, Recently i got an error msg looks like this: you cannot use subqueries within a sqldatadpter except the subquery is introduced with EXISTS. Well, actually i was using IN. I know I can revise my query sting to use INNER JOIN or such stuff just to remove the nested queries. But i'm realllllly curious why it's not allowed?? Really appreciate it if some expert can tell me. Thanks in advance
Hi what i like to do is insert in one table 2 value from 2 different row. exp: table1: person id name 1 bob 2 john so id like to make an insert that will result in this table 2: person_knowed idperson1: 1 idperson2: 2 so the wuery should look something like this:
insert into person_knowed(idperson1, idperson2)(select id from personwhere name = 'bob',select id from personwhere name = 'john')); anybody have an idea of how to acheive this?
Hello, How can I do something like: Insert Into Displayed(snpshot_id, user_id, user_domain, ddisplay, iWidth, iHeight, disp_size, disp_format, watermark, frc_update, creditcost) Values ((Select snpsht_id from SiteIndex Where user_domain like '%domain'), 1000, (Select domain_id from UserDomains Where user_domain like 'domain'), GetDate(), 480, 360, 2, 1, 1, 0, 3) Im getting an error: Subqueries are not allowed in this context. Only scalar expressions are allowed.
I wonder if somebody could give me advice on SQL Server7-specific handling of subqueries and backreferences...
What is a) more efficient, and b) faster:
1. IF (DATEDIFF(minute, ( SELECT tLastHitTime FROM ( SELECT * FROM tblSession WHERE tSessionID = 'abcd1234' ) as sess), getDate()) < 30) SELECT * FROM sess
or:
2. IF (DATEDIFF(minute, ( SELECT tLastHitTime FROM tblSession WHERE tSessionID = 'abcd1234' ) as sess), getDate()) < 30) SELECT * FROM tblSession WHERE tSessionID = 'abcd1234'
In the first example, 2 SELECT statements (line 2 & line 8) refer to derived table by its alias 'sess'. In the 2nd example, both queries are independant, yet identical...
I wonder if SQLServer is "smart" enough to execute identical queries only once, and then reuse the resulset (e.g. derived table), or it requires explicit references (such as alias) in order to do so...
i have a problem, i have a query which does a search based on a parameter, thing is i want to order them according to how relevant the results are such as 5 for beingan exact match, 0 for being no match. using a series of liek statements.
so that the most relevnat results are displayed at the top.
how do i achieve this - im a bit confused about this.
hi there, I have a query that works on sybase and want to make it also works on SQL Server. The problem is that in this query I 'm using a subquery in an aggregate function. It seems that SQL Server unlike Sybase doesn't support the use of subquery in aggregate function. How can I overcome this problem.
To make a long story short, I'm trying to correlate the most inner query (two levels deep) with the most outer one, and it just doesn't work. Is it because the correlation must be back-to-back, without any levels that stand before the two?
If you have no idea what I'm talking about, below is the query that does work, but doesn't produce the right results ("QUOTES" gives the same number for all records):
---------------
select printersGlobal.company, (select count(*) from (select subBidding.bid_company from bidding as subBidding where subBidding.bid_company = 'Printing Company 1' group by subBidding.bid_company, subBidding.project) group by subBidding.bid_company) as QUOTES,
count(date_picked) as wins
from printers as printersGlobal
left outer join bidding as biddingGlobal on printersGlobal.company = biddingGlobal.bid_company group by printersGlobal.company order by printersGlobal.company asc
----------------------
When I replace 'Printing Company 1' with printersGlobal.company (to correlate and produce dynamic and correct results), I get errors.
I would appreciate if anybody can point me in the right direction.
Hopefully someone can suggest a better solution than what I'm currently hobbling along with.
Basically, I've got a table that gets rows inserted (with a timestamp) whenever there is a change to one of the values of a particular "item". So, what I want is to return a dataset of the latest values of each particular item.
I'm guessing that what I'm trying to acheive is doable in some elegant and performant fashion. Something maybe involving a ROLLUP or WITH CUBE or some FANCY item.
But for the time being, I've got a less-elegant query that returns the correct data, just using subqueries.
-- JUST DISPLAY THE TABLE FOR EXAMPLE SELECT * FROM @actionHistoryTable
-- THIS ROLLS-UP THE LATEST VALUE FOR EACH ACTION_TYPE FOR EACH ITEMID SELECT aht.itemID ,( SELECT TOP 1 aht2.actionValue FROM @actionHistoryTable aht2 WHERE aht.itemID = aht2.itemID AND aht2.actionType = '1' ORDER BY aht2.actionTime DESC ) as 'latest type 1 value' ,( SELECT TOP 1 aht2.actionValue FROM @actionHistoryTable aht2 WHERE aht.itemID = aht2.itemID AND aht2.actionType = '2' ORDER BY aht2.actionTime DESC ) as 'latest type 2 value' ,( SELECT TOP 1 aht2.actionValue FROM @actionHistoryTable aht2 WHERE aht.itemID = aht2.itemID AND aht2.actionType = '3' ORDER BY aht2.actionTime DESC ) as 'latest type 3 value' FROM @actionHistoryTable aht GROUP BY aht.itemID
