I am struggling with the sequence of parameters in my where clause.
In my databse table i have index on Broadcast_Date(some table field).The Index also include some other parameters which might become part of where clause.
The first field of the index is broadcast date.
So I want to know whether it is always compoulsory to have broadcast date as my first field of where clause.
Will it not scan the index if my where clause is starting with any other field which is also part of index.?
where c.Planid = '91' and c.Pay = c.mon and c.= '2006-12-01 00:00:00' and (c.Hp<>'1'
or c.ES <>'1' or c.FactorType not in ('D', 'I1', 'I2')
or m.DOD IS NULL )
What I am trying to get in the above example is to exclude some of the rows from select in the where caluse. so if either one of these are not hp<>'1' or ES<>'1' or FactorType not in ('d', 'l1', '12') or dod is not null) should not be include in the select.
so HP should not be equal to 1, ES should not be equal to 1 or factortype no in d l1, or 12 or dod is null. but some how I am getting those recrods where HP is 1 or ES is one and even dod is not null .
Hi all, thanks in advance for reading this and trying to help me with finding a solution this little problem.
I have the following table:
if object_id('tempdb..#VehMakeVehModel') > 0 drop table #VehMakeVehModel
create table #VehMakeVehModel ( VehMake varchar(20) ,VehModelId int identity(1, 1) ,VehModel varchar(50) ,VehTransmission char(1) ,VehFuelType char(1) ,NumberOfDoors int ,ManufacturedFrom int ,ManufacturedTo int )
insert into #VehMakeVehModel select 'VOLKSWAGEN', 'GOLF GT TDI (110)', 'A', 'D', 4, 1980, 1995 union all select 'VOLKSWAGEN', 'GOLF GT TDI (110)', 'A', 'P', 4, 1996, 1997 union all select 'VOLKSWAGEN', 'GOLF GT TDI (110)', 'M', 'P', 5, 1998, null
As you can see, this table holds information about various vehicle makes and models. I've only included 3 sample records as I believe that should be sufficient for this exercise.
I am trying to develop a stored procedure where I pass a table holding vehicle histories of people and update the missing VehModelId in that table. Sounds simple enough right? Well not quite.. The table that I pass to the stored procedure looks something like this:
if object_id('tempdb..#myStagingTable') > 0 drop table #myStagingTable
create table #myStagingTable ( PersonId int ,VehMake varchar(20) ,VehModel varchar(50) ,VehModelId int ,VehTransmission char(1) ,NumberOfDoors int )
insert into #myStagingTable select 101, 'VOLKSWAGEN', 'GOLF GT TDI (110)', null, 'A', 4 union all select 102, 'VOLKSWAGEN', 'GOLF GT TDI (110)', null, 'M', 5
To update the missing VehModelId in the second table I can write an update statement like so:
update a set VehModelId = b.VehModelId from #myStagingTable as a inner join #VehMakeVehModel as b on a.VehMake = b.VehMake and a.VehModel = b.VehModel
That is obviously wrong as this update assigns the same VehModelId for both records. We can include the VehTransmission and NumberOfDoors columns in our update like so:
update a set VehModelId = b.VehModelId from #myStagingTable as a inner join #VehMakeVehModel as b on a.VehMake = b.VehMake and a.VehModel = b.VehModel and a.VehTransmission = b.VehTransmission and a.NumberOfDoors = b.NumberOfDoors
This looks better but if you notice, the update has assigned the same VehModelId for the first two rows which is incorrect. Obviously the more information we have, for example Yearmanufactured etc.. will allow for better matches but in this instance, I would reject the update as more than one record is matching.
I hope that so far, this part of my problem makes sense. Now on to the serious bit. How can I make the WHERE clause dynamic?! What if my staging table varies? So sometimes, I might have a Staging table that has VehTransmission only, or sometimes I have VehTransmission and FuelType AND NumberOfDoors?
There is an int filed in my table called "WeekNo" and when I use order by WeekNo Desc, I am getting the following result. 9 8 7 7 6 5 4 3 2 18 17 16 15 15 14 13 13 12 11 10 10 1
This does not seem right, can anyone comment why i am getting this result.
I'm working to improve performance on a database I've inherited, and there are several thousand indexes. I've got a list of ones which should definitely exist within the database, and I'm looking to strip out all the others and start fresh, though this list is still quite large (1000 or so).
Is there a way I can remove all the indexes that are not in my list without too much trouble? I.e. without having to manually go through them all individually. The list is currently in a csv file.
I'm looking to either automate the removal of indexes not in the list, or possibly to generate the Create statements for the indexes on the list and simply remove all indexes and then run these statements.
As an aside, when trying to list all indexes in the database, I've found various scripts to do this, but found they all seem to produce differing results. What is the best script to list all indexes?
So I'm reading http://www.sql-server-performance.com/tips/clustered_indexes_p2.aspx and I come across this: When selecting a column to base your clustered index on, try to avoid columns that are frequently updated. Every time that a column used for a clustered index is modified, all of the non-clustered indexes must also be updated, creating additional overhead. [6.5, 7.0, 2000, 2005] Updated 3-5-2004 Does this mean if I have say a table called Item with a clustered index on a column in it called itemaddeddate, and several non-clustered indexes associated with that table, that if a record gets modified and it's itemaddeddate value changes, that ALL my indexes on that table will get rebuilt? Or is it referring to the table structure changing? If so does this "pseudocode" example also cause this to occur: sqlstring="select * from item where itemid=12345" rs.open sqlstring, etc, etc, etc rs.Fields("ItemName")="My New Item Name" rs.Fields("ItemPrice")=1.00 rs.Update Note I didn't explicitly change the value of rs.fields("ItemAddedDate")...does rs.Fields("ItemAddedDate")=rs.Fields("ItemAddedDate") occur implicitly, which would force the rebuild of all the non-clustered indexes?
I have a requirement to only rebuild the Clustered Indexes in the table ignoring the non clustered indexes as those are taken care of by the Clustered indexes.
In order to do that, I have taken the records based on the fragmentation %.
But unable to come up with a logic to only consider rebuilding the clustered indexes in the table.
Does anyone have the idea why the Indexes with _WA.....(like _WA_Sys_au_fname_07020F21) gets created.I don't how this index got created. I did not create this Index. My Question is does the system creates these indexes or something else does this. Thanks Chak
Is there a way to tell how many indexes exist for an entire database, all I'm looking is for a count or generating a report list. any help would be appreciated, thank you
At present I have been assigned to create indexes to retrieve the information fast, from the table. The existing table doesn’t have primary key, foreign key and unique constraints but I found to many default indexes already created by the system. I would like to know how this happened? Please inform how to delete these default indexes. Further, inform me other possible ways for the faster retrieval in SQL sever 7.0, if there are any.
I would appreciate if you send me a step by step explanations for the above problems.
I have run into a snag on my development server. Queries that are selecting data based on indexed fields in a where clause are using the wrong indexes. They are arbitrarily using the clustered index which isn't in the select at all and causing big performance problems. I can run the same statements on my production server and it runs based on the proper indexes. I used query execution plans to determine that this was infact the case.
I run DBCC Checkdb everynight and it comes back with no errors. I also rebuild the indexes. We also don't receive any other errors inputting or updating data. This sounds like corruption to me but if it's something else I don't want to spend the night restoring from production if there is another reason.
Is there any way for me to find out when last indexes have been used so that the one I don't need can be dropped.And also the one's that are of no use at all. I need this as i am trying to dump all duplicated indexe . i know i can do this in ver 7
when executed sp_help tablename, I get lot of statistics and indexes like the following. Can anyone please tell me how it is generated automatically. as far i know statistics are generated only for primary keys. Can you please tell me what is clustered , hypothetical and the indexes starting with _WA supposed to be. Also there are lot of duplicate stats. Is it Ok to deletes those. _WA_Sys_is_platinum_0A9D95DB _WA_Sys_active_0A9D95DB nonclustered, statistics, auto create located on PRIMARY Active hind_c_33_15 nonclustered, statistics located on hind_c_37_1 clustered, hypothetical located
I have a question about speed and indexes. I have a static table (no updates except once a year). I want to be able to search data quickly on one column or many columns. I have created nonclustered indexes on each of the columns I search by. Is there anything else I can do to speed up my queries? Unfortunately all the searches involve using the like operator. I have even broken my table down into 2 smaller tables (Table A ~ 3 million rows, Table B 8 million rows).
I need to alphabetize PART of a union all query, and was told that this may be accomplished with an index. I tried joining two views, but it does not work! I have NO experience with indexes and need some help.
Here is my code:
Select id, country from countries where id = 6 union all Select id, country from countries where id <> 6
I want the country with id 6 (USA) to be the default on a drop down list, then all the other countries listed after it in alphabetical order. Can you do this with an index? If so, how do I proceed?
We recently updated some of the databases from MS Access 2000 to SQL Server 2000. In Access we had columns which were set to Indexed No Duplicates, these were not Primary key fields. Is this possible to set some indexes to prevent duplicates in SQL Server without creating performance issues?
Q1 The table i have stores max 2000 records. Not sure if i neeed a clustered index for this few records. I guess not.
Q2 For the same table as above. How do you create primary keys if there is not unique records. Do i create a new column? like newColumnID identity? and create a primary key on this new column? Ok even if i create this newcolumn. I don't think it will improve the retrieving speed cause i'm not selecting this column.
i am running a stored procedure which has got clustered indexes created after creating table and data is inserted into it after creating clustered indexes. The tables which are meant in this sp is temporary tables and how to gain the performance of a query
I've created indexes for the queries below running select getdate() before and after the query to determine the time. I'm curioius as to how sql server determines and decides how and when to use the indexes for the queries and how the run times of these queries compare. I'm also curious to know what kind of difference there would be on the last two queries as the only difference is the values. For the last two queries I don't think there would be a difference but hoping that someone would know.
Below are my results:
select count(distinct CustomerID) from Orders where Status = 5
SELECT getdate() go Create Index Orders_Index On Orders(customerID) go SELECT getdate()
select sum(TotalDue) from Orders where CustomerID = 11212
select getdate() go Create Index Orders_Index On Orders(customerID) go select getdate()
select count(distinct AccountNumber) from Orders where SalesPersonID = 288
select getdate() go Create Index Orders_Index On Orders(salespersonID) go select getdate()
select count(distinct AccountNumber) from Orders where SalesPersonID = 276
select getdate() go Create Index Orders_Index On Orders(salespersonID) go select getdate()
I have a very large table (about 200,000 records), but there are only 2 fields in the table only one populated with data. I need to update the 2nd field with the first field's data.
UPDATE Table1 SET field2 = field1
This is taking a really long time to run about 3.5 minutes. Is this normal? Can I create an index? What can I do to shorten the run time?
Aren't all indexes created as separate structures from a table? Although the index is created against a particular table, doesn't the index itself exist in the database as a separate, self-contained structure?
Which index type -- clustered or nonclustered -- logically sorts the database of a table?
I need some help in deciding for the best index design possible for my requirements. Well basically i have 3 tables (lets call it T1, T2 and T3 ). T1 is only used like a source... T2 is a source and destination... T3 is only a destination table.
Lets suppose all tables have the same columns structure. In the first phase i insert records from T1 into T2 using lots of different queries filters like this: WHERE Col1 = x AND Col2 IN (A and B) AND Col3 Between Int1 and Int2 AND Col4 = y
Other queries looks the same but diferent column is used in the Col4 place... so it can be Col5, 6 or 7 for example.
In the second phase i do the same but from T2 into T3...
Whats the best index design in this case?
Should i disable indexes in the destination table T2 while i am loading it and the rebuild? This can take alot of time, any other way? Is it best to leave it enabled all the time?
What kind of indexes should i create? Multi Column indexes or single ones for Col1, 2 3 4 5 6.. etc??
