Implicit Vs Explicit Joins
May 20, 2008performance wise what is the difference between following queries
Select * from A, B Where A.ID = B.ID
Select * from A INNER JOIN B ON A.ID = B.ID
(ID is the primary key)
performance wise what is the difference between following queries
Select * from A, B Where A.ID = B.ID
Select * from A INNER JOIN B ON A.ID = B.ID
(ID is the primary key)
Is there any difference between explicit inner join and implicitinner joinExample of an explicit inner join:SELECT *FROM employeeINNER JOIN departmentON employee.DepartmentID = department.DepartmentIDExample of an implicit inner join:SELECT *FROM employee, departmentWHERE employee.DepartmentID = department.DepartmentID
View 11 Replies View RelatedWe are trying to migrate from sql 2005 to 2012. I am changing one of the implicit join to explicit join. As soon as I change the join, the number of rows returned are fewer than before.
Below is my Implict join query
INSERT #RIF_TEMP1 (rf1_row_no,rf1_rif, rf1_key_id_no, rf1_last_date, rf1_start_date)
SELECT currow.rf0_row_no, currow.rf0_rif, currow.rf0_key_id_no, prevrow.rf0_start_date, currow.rf0_start_date
FROM #RIF_TEMP0 currow , #RIF_TEMP0 prevrow
[Code] ....
and below is explict join query
INSERT #RIF_TEMP1 (rf1_row_no,rf1_rif, rf1_key_id_no, rf1_last_date, rf1_start_date)
SELECT currow.rf0_row_no, currow.rf0_rif, currow.rf0_key_id_no, prevrow.rf0_start_date, currow.rf0_start_date
FROM #RIF_TEMP0 currow LEFT JOIN #RIF_TEMP0 prevrow
ON (currow.rf0_row_no = prevrow.rf0_row_no + 1)
[Code] ....
the count returned from both the queries is different.
I am not sure what am I doing wrong. The count of #RIF_TEMP0 is always 32, it never changes, but the variable @countTemp is different for both the queries.
We find that a delete command on a table where the rows to be deleted involve an inner join between the table and a view formed with an outer join sometimes works, sometimes gives error 625.
If the delete is recoded to use the join key word instead of the = sign
then it alway gives error 4425.
625 21 0 Could not retrieve row from logical page %S_PGID by RID because the entry in the offset table (%d) for that RID (%d) is less than or equal to 0. 1033
4425 16 0 Cannot specify outer join operators in a query containing joined tables. View '%.*ls' contains outer join operators.
The delete with a correleted sub query instead of a join works.
Error 4425 text would imply that joins with view formed by outer joins should be avoided.
Any ideas on the principles involved here.
I have a report that has 3 nested lists. The report looks fine when I view it in the browser but when I print it or export it to another format it appears that keep together is on for each list because some pages are only partially filled. I do not have keep together turned on for any report control, and I don't have page break turned on for anything. This problem results in the report being many more pages than it needs to be. Can anyone help?
View 4 Replies View RelatedSQL Server 2000Howdy All.Is it going to be faster to join several tables together and thenselect what I need from the set or is it more efficient to select onlythose columns I need in each of the tables and then join them together?The joins are all Integer primary keys and the tables are all about thesame.I need the fastest most efficient method to extract the data as thisquery is one of the most used in the system.Thanks,Craig
View 3 Replies View RelatedHi,
I have noticed that implicit casts are allowed according to the actual data in a column.
Here is an example:
SELECT * FROM MyTable WHERE MyColumn = 3897
MyColumn is defined as nvarchar(15) not null in the database schema.
This query will work only if there are no record in MyTable for which MyColumn has an alphanumerical value. Otherwise it will raise an error:
Serveur : Msg 245, Niveau 16, État 1, Ligne 1
Syntax error converting the nvarchar value 'C061' to a column of data type int.
Of course, the following query is always successful:
SELECT * FROM MyTable WHERE MyColumn = '3897'
Am I correct?
Thanks a lot.
Hello, everyone:
I need total transaction count. @@TRANCOUNT returens the number of explicit transaction. How about implicit transaction? Thanks a lot.
ZYT
Hi Everyone-
i have a report that include parameters that the user set and press the button ViewReport for rendering the report
until that everything ok,.. .......but assume that there is an updating occurred on data after the user make the first press on the button ViewReport.
The problem is if the user press the button ViewReport again for the second time without changing the parameter value the report result will be the same even though it is the old data that appear in the 1st press button.
can anyone tell me how to handle this problem to make it refresh when the ViewReport button is pressed
or if there is no solution can anyone provide me with a link that talks about that problem for more details
thanx
Maylo
Is there a way do disable/disallow implicit casting in Sql Server 2000?
Say for example:
if ' ' = 0 select getdate()
This wil print out the current date and time.
But ' ' (a string, varchar, whatever) is not the same type as 0 (say, int). Implicit casting is nice, but is there also an off switch?
Hi all,
I am running into a problem which seems to indicate SQL Server 2005 is pretty aggressive with its implicit conversion which makes UNPIVOT apparently unusable for my current task of creating attribute/value pairs of strings for each of the records unpivoted around the primary key.
WITH cte as
(
SELECT 1 as Code, '2' as Status, 'Some Guy' as CreatedBy, Convert(varchar(19), getdate(), 120) as CreatedDate
)
SELECT
[Code]
,[Attribute]
,[Value]
FROM
cte
UNPIVOT([Attribute] FOR [Value] IN ([Status],[CreatedBy],[CreatedDate])) as U;
Msg 8167, Level 16, State 1, Line 1
The type of column "CreatedBy" conflicts with the type of other columns specified in the UNPIVOT list.
The same result shows up if I use an inner SELECT instead of the CTE:
SELECT
[Code]
,[Attribute]
,[Value]
FROM
(
SELECT 1 as Code, '2' as Status, 'Some Guy' as CreatedBy, Convert(varchar(19), getdate(), 120) as CreatedDate
) cte
UNPIVOT([Attribute] FOR [Value] IN ([Status],[CreatedBy],[CreatedDate])) as U;
It seems to me that some arbitrary decision about what column is processed first is made and the process fails as soon as a column is met which is not of the same datatype. I also think it is interesting that the engine will implicitly cast from varchar to DateTime but not the other way around.
Any thoughts on how I can get around this?
Thanks in advance,
Calvin
If I execute multiple SqlCommands in a single .aspx, using a single SqlConnection, are all the commands part of the same transaction?
That is, if I say:
cmd1.CommandText = "UPDATE foo SET myVal = myVal - 1"
cmd2.CommandText = "SELECT myVal FROM foo"
cmd1.Connection = myConn
cmd2.Connection = myConn
myConn.Open()
cmd1.ExecuteNonQuery() ' decrement myVal
intResult = CInt(cmd2.ExecuteScalar()) ' select value of myVal
myConn.Close()
Do the UPDATE and the SELECT happen in the same transaction, or is it possible that someone else would have changed the value of myVal between these two calls?
I am trying to construct a query in Query Analyzer (with SQL Server 2000), but am getting an error regarding "implicit conversion."
Here is the query:
SELECT dbo.AUCTION.EbayNum, dbo.AUCTION.EndDate,
DATENAME([month], dbo.AUCTION.EndDate) + ' ' + DATENAME([year], dbo.AUCTION.EndDate) AS [PmtMonth],
dbo.LOT.Description, dbo.AUCTION.WinBid,
PaidStat = CASE dbo.AUCTION.PaidStatus
WHEN 0 THEN ''
ELSE 'PAID'
END,
PaidAmt = CASE dbo.AUCTION.PaidStatus
WHEN 0 THEN ''
ELSE dbo.AUCTION.WinBid
END
FROM dbo.AUCTION INNER JOIN
dbo.LOT ON dbo.AUCTION.LotNum = dbo.LOT.LotNum
WHERE (LEN(dbo.AUCTION.Winner) > 0)
The error occurs in the PaidAmt CASE statment:
"Implicit conversion from data type varchar to money is not allowed. Use the CONVERT function to run this query."
Why is there an implicit conversion going on? And how can I fix it? :mad:
Dear all,
Hi, I'm using this code to export record from sql to excel and i got this error message "Implicit conversion from data type text to nvarchar is not allowed. use the convert function to run this query"
Excel file is already created columns in the view and excel file are the same and cell format of the excel is converted to text.
--- code used
insert into OPENROWSET('Microsoft.Jet.OLEDB.4.0',
'Excel 8.0;Database=c:filename.xls;',
'SELECT * FROM [filename$]') select * from ViewName
thanks,
I have a sql statement that must run in both sql server and oracle. I can't change the sql statement as it is created as part of a core application from Rational Rose.
Basically the problem is that I have a table with a column defined as a decimal type in sql server (numeric in oracle).
The select statement, however, treats the column as a char. I can reproduce the problem with this simple code:
create table atest2 (a decimal(9,0))
insert into atest2 values (1)
insert into atest2 values (2)
insert into atest2 values (null)
insert into atest2 values (4)
select * from atest2 where a = ' '
This gives the error:
Error converting data type varchar to numeric.
The documents seem to indicate the sql server will implicitly convert decimals to varchar but this doesn't seem to be happening. Is there an environment setting that might control this?
Thanks,
Rut
have a sql statement that must run in both sql server and oracle. I can't change the sql statement as it is created as part of a core application from Rational Rose.
Basically the problem is that I have a table with a column defined as a decimal type in sql server (numeric in oracle).
The select statement, however, treats the column as a char. I can reproduce the problem with this simple code:
create table atest2 (a decimal(9,0))
insert into atest2 values (1)
insert into atest2 values (2)
insert into atest2 values (null)
insert into atest2 values (4)
select * from atest2 where a = ' '
This gives the error:
Error converting data type varchar to numeric.
The documents seem to indicate the sql server will implicitly convert decimals to varchar but this doesn't seem to be happening. Is there an environment setting that might control this?
Thanks,
Rut
Hi:
I get this following error when I run try to insert a record from the DetailsView. Please help me out.
---------------------------------------------------------------------------------------------------------------------
Disallowed implicit conversion from data type sql_variant to data type uniqueidentifier, table 'getsetwin.lax21.tblCreateGoal2', column 'ApplicationId'. Use the CONVERT function to run this query.Disallowed implicit conversion from data type sql_variant to data type uniqueidentifier, table 'getsetwin.lax21.tblCreateGoal2', column 'UserId'. Use the CONVERT function to run this query.Operand type clash: sql_variant is incompatible with image
---------------------------------------------------------------------------------------------------------------------
Thank you & Best regards,
Lax
Hi I get the following error:
Implicit conversion of varchar value to varchar cannot be done
because the collation of the value is unresoved due to a collation
conflict
SELECT
Accounts_Users.NameFirst + ' '
+ Accounts_Users.NameLast + ' (' + Accounts_Users.BusinessUnit + ')' AS
NameFull, -- Error here
-- Accounts_Users.NameFirst + ' ' + Accounts_Users.NameLast AS NameFull, -- This line works
Accounts_Users.EmailAddress, Accounts_Users.BusinessUnit
FROM Accounts_Users.Accounts_Users
NameFirst and NameLast are VarChar(30) and BusinessUnit VarChar(50), I
did try converting it to 30 also but still got the same error
The sp works on my dev sql server but not on the live one, I am using Management Console v2 (dev) and 1.2 (live server)
Thanks
Steve
Good Afternoon
Hope that somone can shed some light...
I am using the HitSoftware driver to pass data to an AS400 from a SQL 7 database. Data makes it fine to 2 of the 4 tables but I cannot get the syntax correct to even get out of the S/P edtitor in SQL for the other 2.
I have fields in the SQL S/P defined as VARCHAR. The target fields on the AS400 are ALPHA. So I figured the insert statement to look like:
INSERT INTO CALICOTOTESTAS400.S105Z1NM.ORDTALIB.itmrva0# (TRID30, ITNO30, ITDS30, ITYP30, INVF30, UMST30, ITAC30, UUCA30, EGNO30, RTID30)
VALUES (@v_action, @v_modelNumber, @v_modelDesc, '1', 1, 'EA', @v_acctClass, @v_modelyear, @v_engRevision, @v_spectype)
However, when I try to close the S/P window I get the error:
Error 257: Implicit conversion from data type varchar to binary is not allowed. Use the CONVERT function to run this query.
So, I changed the insert statement to this:
INSERT INTO CALICOTOTESTAS400.S105Z1NM.ORDTALIB.itmrva0# (TRID30, ITNO30, ITDS30, ITYP30, INVF30, UMST30, ITAC30, UUCA30, EGNO30, RTID30)
VALUES (CONVERT(binary, @v_action), CONVERT(binary, @v_modelNumber), CONVERT(binary, @v_modelDesc), CONVERT(binary, '1'), 1, CONVERT(binary, 'EA'), CONVERT(binary, @v_acctClass), CONVERT(binary, @v_modelyear), CONVERT(binary, @v_engRevision), CONVERT(binary,
@v_spectype))
Now the S/P closes without the error. But when I send it to the AS400 I get unrecognizable characters in the fields.
Then I started thinking...I am not trying to do anything with binary fields.
So I am really lost. Please help.
Thanks,
Ed 330-273-7521
If i create a simple table with a foreign key constraint, does itcreate an implicit index on that given ID? I've been told this isdone in some databases, but i need to know for sure if SQL Server doesit. Has anyone heard of this before, on any other databses perhaps?Heres an example of how the foreign key constraint is being added:ALTER TABLE [dbo].[administrators] WITH CHECK ADD CONSTRAINT[FPSLUFSUOXZGAJOJ] FOREIGN KEY([AdministratorRoleID])REFERENCES [dbo].[administratorroles] ([AdministratorRoleID])My initial testing seems to indicate adding an index on the foreignkey column helps, but i need to know for sure. Any insight would begreatly appreciated!Bob
View 6 Replies View RelatedHi all:
I know i can use the sentence SET IMPLICIT_TRANSACTIONS ON in a Stored Procedure to force SQL Server to set the connection into implicit transaction mode.
Have i a sentence or configuration to force all SQL Server connections to implicit transaction mode?
Thanks in advance.
is anybody using this? it looks like a lot of trouble to return a formatted string. I am considering it for something. Any opinions?
http://technet.microsoft.com/en-us/library/aa226532(SQL.80).aspx
caution: you have to X out of the Do You Want to Download Silverlight popup.
i have a situation, where i need to group my information by a certainid, but that information which should already be grouped, i need toorder based on a number in one of the columnsexample:<ex id=2 listorder=1><description>desc 2</description></ex><ex id=1 listorder=2><description>desc 1</description></ex>in my order clause i first put order by the id, and it will group theinformation accordingly, but will put the lowest number id first, notcaring about the listorderbut if i order by the listorder column first, the information isn'tgroupd properlyi don't know if i made myself clear enough?hope someboyd can help methnx in advance
View 1 Replies View RelatedHere is the situation...
I am using SQL Server 2000. I have created a Store Procedure to
insert information, 4 of the fields are date types. I am using
OleDb Data Provider (System.Data.OleDb) namespace.
The dates are filled by a form (web form) on submit event, I created a
class that has functions to create my OleDb Parameters. I add the
parameters to the command and execute it through a SQL Server Stored
Procedure. In the event that I must have coded something wrong, I
tested in the SQL Query Analyzer and the IN parameters for the date I
used the getDate() method. This is where I know it is OleDb and
SQL Server Parameters.
What Converstion Format should I use in the SP for the date?
OleDb.date are doubles from some date in 1979 or something or
another. So I used an OleDbDataType.DBDate. It seems that
when the Stored Procedure uses the IN Parameters dates provided by
OleDbDataType.Date or DBDate, that it doesn't like the int
format. I am guessing that I am not converting the date in the
parameters in the Insert of the Store Procedure... this is basically
what I have...
Function to add parameters and execute SP
private int _startdate = DateTime.Now;
private int _finishdate = DateTime.Now.AddDays(30);
OleDbParameter[] myParams = {
ParamBuilder("@StarDate", OleDbType.DBDate, 8, _startdate),
ParamBuilder("@FinishDate", OleDbType.DBDate, 8, _finishdate)
};
ExecuteNonQuery("myInsert", myParams);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CREATE PROCEDURE myInsert
@StartDate datetime, @FinishDate datetime AS
INSERT INTO myTable (STARTDATE, FINISHDATE)
VALUES (Convert(datetime, @StartDate), Convert(datetime, @FinishDate))
Please keep in mind that I am using System.Data.OleDb
namespace..... please don't tell me to use SQLClient, it seems
since I've been so adaptive of using OleDb, that it sould work just as
well. I am way too far into this to change my Provider to SQL
Client, but I promise myself that the next project (if using SQL
Server, I will be using SQLClient and I will keep using OleDb for
Oracle.) *sigh*
Help!
In a stored procedure, the following code is causing a huge read and CPU load when it really shouldn't. The @IDParameter below is coming in as a parameter to the proc.
Here's the snippet of code where the problem is coming in:
DECLARE @ID INT;
SET @ID = (SELECT ID From OtherTable WHERE FKID = @IDParameter);
SELECT COUNT(*)
FROM LargeTable
WHERE MostlyZeroID = @ID AND MostlyZeroID > 0Most (90+%) of the MostlyZeroID rows are 0 (hence the name) but regardless of distribution this should evaluate with minimal work on SQL Server's part to 0. However, when this was run, it is using a ton of CPU and doing a ton of Reads as it seeks through the entire index. When I look at the execution plan, I see under the seek predicate a Scalar Operator(CONVERT_IMPLICIT(int,[@1],0)) which is what is destroying the performance.
I've confirmed that the MostlyZeroID column in the LargeTable is defined as an INT NOT NULL. I also tested the scenario outside the stored procedure without any variables as the following to make sure it wasn't some kind of strange parameter sniffing scenario:
SELECT COUNT(*)
FROM LargeTable
WHERE MostlyZeroID = 0 AND MostlyZeroID > 0
However, this query also did the implicit conversion. I then tried this out on a temp table populated with a similar number of records (100 million) with a similar distribution and I didn't get the implicit conversion (I got a constant scan as I would've expected) when I did this:
SELECT COUNT(*)
FROM #TestTable
WHERE MostlyZero = 0 AND MostlyZero > 0
I also tried the same on several other tables that are set up similarly (large amount of zeros in an INT column) and I always got a constant scan and didn't do an implicit conversion.
why the query engine is interpreting this 0 as something other than an INT and doing an implicit conversion when getting the count in the scenario above? What can be done to protect against it? In the above scenario, an IF @ID > 0 statement was placed before the code including the count since there was no reason to even run the code if the @ID was equal to zero.
I am facing a problem while using SQL Server with VB application.Implicit conversion from datatype text to nvarchar is not allowed.Use the convert function to run this query.When i see the trace file, i see one stored procedure called but nolines of code get executed, and immediately after that the ROLLBACKTRANSACTION occurs and the applications fails.But to my surprise i am able to do the same thing on a differentmachine using the same application and the same database on the sameserver with the same user id.Can anyone explain the reason of occurance of this problem.I require this very urgently, so i will be oblized if anyone can comeup with a quick response.Kind Regards,Amit Kumar
View 5 Replies View RelatedWhen I run this ...
CREATE ASSEMBLY asmRANDRTCalendaringGateway FROM 'E:sqlRANDRTCalendaringGateway.dll' WITH PERMISSION_SET = UNSAFE
I get this error ...
Msg 10301, Level 16, State 1, Line 1
Assembly 'RANDRTCalendaringGateway' references assembly 'system.web, version=2.0.0.0, culture=neutral, publickeytoken=b03f5f7f11d50a3a.', which is not present in the current database. SQL Server attempted to locate and automatically load the referenced assembly from the same location where referring assembly came from, but that operation has failed (reason: 2(The system cannot find the file specified.)). Please load the referenced assembly into the current database and retry your request.
Even though I do not explicity refer to system.web in the DLL's code ...
using Microsoft.Win32;
using System;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Collections.Generic;
using System.Configuration;
using System.Text;
using log4net;
using ADODB;
using MAPI;
using CDO;
using System.Runtime.InteropServices;
Is the problem just staring me in the face ?
cheers
Hi ,
I've tried to switch MS-Sql/Server 6.5 on explicit_transactions
without success.
(set implicit_transaction on/off)
What is the exact syntax for doing that ?
Herve
(PS: Thanks Gregory for your quick answer )
Hi All,
I don't know MS-SQLserver internal system at all. I 've just used Oracle
a couple years ago and so in some cases (e.g using TP-monitor MTS or Tuxedo)
you can switch off the implicit transaction by using
the option AUTOCOMMIT ON/OFF.
How can switch off the implicit transaction system on MS-SQLServer ?
In advance thanks,
Herve
I created a SELECT statement that uses the FOR XML EXPLICIT clause so that SQL Server data can be exported to another system. Format thios system accepts is XML. What should I define within a DTS package so that this Select statement is executed and an XML file is created?
View 12 Replies View RelatedI have an cursor that loops 720 times.
Each FETCH does 6 INSERTS.
Each FETCH the 6 INSERTs a total of 200-300 records appended.
Would explicit transactions speed up the cursor?
In Oracle, I would keep track of how many times I've looped, and commit every nth time. I would put a catch remainder COMMIT at the end of the procedure.
I've got the IF @@TRANCOUNT > 19 COMMIT TRAN (about 6k records), but say I had <= 19 remaining at the end of the cursor, how do you get those to commit? I tried to put an IF @@TRANCOUNT > 1 COMMIT TRAN, but that didn't work.
What's a good @@TRANCOUNT to commit at in this case?
Thanks crew,
Carl
Hello,
In the SP below, I get the following error when I run it:
Explicit value must be specified for identity column in table 'Tests' when IDENTITY_INSERT is set to ON.
From what I've read of the INSERT method, it says you can add a variable value. So I don;t understand why it won't take mine.
CREATE PROC qaspAddTestRecord AS
DECLARE @aKey bigint
DECLARE @aTestSuiteId bigint
exec qaspGetNewID 'Tests', @aKey OUT
SELECT @aTestSuiteId= NewID FROM ID WHERE TableName='TestSuite'
SET IDENTITY_INSERT Tests ON
INSERT INTO Tests (TestSuiteId, TestIDInternal) VALUES (@aTestSuiteId, @aKey)
SET IDENTITY_INSERT Tests OFF
GO
--PhB
Hello all,I'm trying to generate some XML directly from MS SQL with thefollowing codeSELECT1 AS tag, NULL AS parent, NULL AS [GoogleCustomizations!1], NULL AS [Annotations!2], NULL AS [Annotation!3], NULL AS [Annotation!3!about], NULL AS [Annotation!3!score], NULL AS [Label!4], NULL AS [Label!4!name]UNIONSELECT2 AS tag, 1 AS parent, NULL, NULL, NULL, NULL, NULL, NULL, NULLUNIONSELECTTOP 503 AS tag, 2 AS parent, NULL, NULL, NULL, 'www.' + domainName, 1 -- score, NULL, NULLFROM tbl_auDomainNameUNIONSELECT4 AS tag, 3 AS parent, NULL, NULL, NULL, NULL, NULL, NULL, '_cse_ad-o6lgdody'FOR XML EXPLICITThe XML it needs to create is as following<GoogleCustomizations><Annotations><Annotation about="www.clickfind.com.au/*" score="1"><Label name="_cse_ad-o6lgdody" /></Annotation><Annotation about="www.lookle.com/*" score="1"><Label name="_cse_ad-o6lgdody" /></Annotation><Annotation about="www.sensis.com.au/*" score="1"><Label name="_cse_ad-o6lgdody" /></Annotation></Annotations></GoogleCustomizations>It is currently creating<GoogleCustomizations><Annotations><Annotation about="www.10000steps.org.au" score="1" /><Annotation about="www.101fm.asn.au" score="1" /><Annotation about="www.aao.gov.au" score="1"><Label name="_cse_ad-o6lgdody" /></Annotation></Annotations></GoogleCustomizations>I cannot get my head around how I can get the label <Labelname="_cse_ad-o6lgdody" />in each element. Does anyone know?Thanks in advance.
View 2 Replies View Related