How Many Included Index Columns Is Too Many?

Oct 4, 2007

I'm using sys.dm_db_missing_index_details to find missing indexes on a database that is currently in testing. After running a bunch of our reports, there are several suggested indexes on 3 or 4 columns that have 15 - 20 included columns. The included columns are mostly varchars ranging from 1 to 150 characters along with a couple of date columns. My index size on that table is already nearly twice the size of the data.

I don't think it's a good idea to add an index with that many columns, but the information I've read on included columns is very general. I'm wondering if there is something about them that I don't understand that would make this a good idea.

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How Dose It Matter For The Non-clustered Index Key Columns And Included Columns?

Apr 24, 2007

Hi, all experts here,

Thanks a lot for your kind attention.

As I am creating the non-clustered indexes for the tables, I dont quite understand how dose it really matter to put the columns in the index key columns or put them into the included columns of the index?

I am really confused about that and I am looking forward to hearing from you and thank you very much again for your advices and help.

With best regards,

Yours sincerely,

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SQL 2012 :: Included Columns In Non-clustered Index

May 8, 2014

I am trying to tune a process that is running slowly. I analyzed the process using the Database Engine Tuning Advisor, and it recommended the creation of 3 indexes, all non-clustered:

1) ColA, include ColB
2) ColA, include ColC
3) ColA, include ColD

So... I created a single non-clustered index on:

4) ColA, include ColB, ColC, ColD

That should do the same thing, right? A look at my execution plan shows that the index I created is being scanned -- 3 times. What is puzzling me, though, is that the Database Engine Tuning Advisor is still recommending I create these 3 separate indexes, even with the index (4) that I created in existence.

If it matters, ColA, ColB, ColC and ColD are all int FKs.

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Impact Of Non-clustered Index With Included Columns On Large Tables

Nov 14, 2011

I would like to know the impacts (if any) of adding nonclustered index with included columns on large tables (these tables are populated by bulk insert from text files).

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SQL Server 2008 :: InPlace Update For Included Columns

Oct 8, 2014

The Delete-Insert update happens for key columns of Indexes and that makes sense.

But I am confused that why Delete-Insert update happens for Included columns of nonclustered indexes, where I expected them to be InPlace updates ???

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Apr 18, 2005

How do you index through a set of Columns Programmatically using SQL. I have a Table all the columns have the same data for different dates. Column names are Col_0, Col_1, Col_2,.....Col_100, Col_101. I need to perform the same calculation on each column to manipulate the data into a different table. Is it possible to do a While loop that changes the Column name in a SELECT statement. I have tried to do this but can't seem to get it to work. Please help !

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How To Index Through A Tables Columns

May 8, 2005

I am trying to index through the columns of MyTable so I can do the same work on all columns. I know how to get the column names from MyTable but when I use @MyColName in the SELECT statement to get MyTable Column 0 Row values I get a table with the column name in each row cell. I can't get the syntax correct to return the value in each cell for that column.
This is a extremely simplified example !!!!!!DECLARE @MyColName nvarchar(30)
--Get the MyTable Column 0 NameSELECT @MyColName = Col_Name(Object_ID('MyTable'), 0)
--Display the MyTable Column 0 Row valuesSELECT @MyColName FROM MyTable --This is the syntax I can not get correct
 
Can anyone help ?
Thanks

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Unique Index On 2 Columns?

Apr 19, 2013

I find to be able to have multiple NULL entries in the following constraint:

Code:

CREATE UNIQUE INDEX my_uidx ON my_table(my_col1,my_col2) WHERE ??? IS NOT NULL;

But is not possible to check multiple columns in "WHERE".

I using SQL Server 2012 Express

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Order Of Columns For Index

Jun 19, 2013

I want to make an index with the following columns, actually together they constitute the PK of the table so the index is created automatically.

The question is witch sort order is the best to have if I want to fetch all rows for one date and one resource? And why?

WHERE Resource = "Car 1" AND Date = "2013-03-03"

Resource, Date, Time

Or

Date, Time, Resource

Below is an example with tree resources, but in reality there can be a lot more and also years of dates.

Car 1, 2013-03-03, 10.00

Car 1, 2013-03-03, 11.00

Car 1, 2013-03-03, 12.00

Car 1, 2013-03-04, 10.00

[Code] ......

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Get Columns In An Index And Their Order

May 20, 2008

Is there a dynamic management view or system procedure which I can use to find out what columns are in an index, what columns are as an INCLUDE in the index and whether or not the column(s) are ascending or descending. This is excluding the utilities I already know about below:

sys.indexes
sys.index_columns
sp_helpindex
dm_db_index_physical_stats
dm_db_index_operational_stats
I only ask because it is a pain to look through the sys.indexes and sys.index_columns tables every time I want to know about what columns are in the index created. I also know that scripting the index would give me the information I need but there must be a better way.

Many Thanks

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Unique Index On X Columns But Not Primary Key

Feb 23, 2006

my table :

CREATE TABLE [dbo].[users] (
[ID] [int] NOT NULL ,
[A1] [nvarchar] (100) NULL ,
[A2] [nvarchar] (100) NULL ,
[A3] [nvarchar] (100) NULL
) ON [PRIMARY]

i must keep ID columns as primary key

ALTER TABLE [dbo].[users] WITH NOCHECK ADD
CONSTRAINT [PK_users] PRIMARY KEY CLUSTERED
(
[ID]
) ON [PRIMARY]


but now A1+A2 must be unique

how can i do it ?

thank you

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Mar 31, 2014

When creating a column store index, are there any reasons not to include all columns, besides index size of course? i.e. will the index be more versatile with more columns or should I treat it exactly like its a standard index, putting only necessary columns, in the correct order?

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Index On Two Columns Doesn't Allow NULL In Both - HELP!

Dec 22, 2005

Table DDL below:The tables I have contain Timesheet information. Each row in thetblTSCollected table contains an entry for an employee into thetimesheet system, specifically by scanning the barcode on their badge.A whole bunch of business logic periodically attempts to "pair" theseinto logically matched scans. For example, some employees will scan inand out of a single place of work. For these there will be a rowwritten to the tblTSRuleApplied table which contains, inter alia andsome redundant data, the fldCollectedID for the two rows. The earlierwill be put into the fldStartTimeCollectedID, and the later into thefldEndTimeCollectedID. Some employees will clock on at their base,then perform sub-duties at different locations during the day, andclock off at their home base at the end of their shift. For these, thesystem would identify the outer records as a matching pair, and thenpair up inner records by location.However, if the employee fails to enter a valid "clocking in and out"pair (for example, if they clock in at the wrong location) the systemneeds to generate a "dummy" "clocking in and out" record for thepayroll department. Ideally, this would have NULL values in thefldStartTimeCollectedID and fldEndTimeCollectedID columns. This wouldalert a user in a different part of the system, where missingtimesheets were being arbitrated, that an employee appeared to havefailed to clock in for that day. Of course, the user could seeon-screen that they had clocked in, but at an incorrect location.Unfortunately, the database designer is not here for the moment (he wasknocked off his bicycle recently), but he put a unique index on thetblTSRuleApplied table that prevents the same value being entered intothe fldStartTimeCollectedID and fldEndTimeCollectedID columns. This isgenerally A Good Thing, since we don't want the same timesheet scan toform both a "clocking on" event and a "clocking off" event.So, is there any way of retaining the requirement that thefldStartTimeCollectedID and the fldEndTimeCollectedID columns may notcontain the same value in a single row, UNLESS that value is NULL inwhich case all is hunky dory. I should add that the clients don't muchcare for Triggers (and neither do I for that matter).Many thanks if you are able to help.Edwardif exists (select * from dbo.sysobjects where id =object_id(N'[dbo].[FK_tblTSRuleApplied_tblTSCollected]') andOBJECTPROPERTY(id, N'IsForeignKey') = 1)ALTER TABLE [dbo].[tblTSRuleApplied] DROP CONSTRAINTFK_tblTSRuleApplied_tblTSCollectedGOif exists (select * from dbo.sysobjects where id =object_id(N'[dbo].[FK_tblTSRuleApplied_tblTSCollected1]') andOBJECTPROPERTY(id, N'IsForeignKey') = 1)ALTER TABLE [dbo].[tblTSRuleApplied] DROP CONSTRAINTFK_tblTSRuleApplied_tblTSCollected1GOif exists (select * from dbo.sysobjects where id =object_id(N'[dbo].[FK_tblTSArbAccept_tblTSRuleApplied]') andOBJECTPROPERTY(id, N'IsForeignKey') = 1)ALTER TABLE [dbo].[tblTSArbAccept] DROP CONSTRAINTFK_tblTSArbAccept_tblTSRuleAppliedGOif exists (select * from dbo.sysobjects where id =object_id(N'[dbo].[FK_tblTSCollected_tblTSRuleApplied]') andOBJECTPROPERTY(id, N'IsForeignKey') = 1)ALTER TABLE [dbo].[tblTSCollected] DROP CONSTRAINTFK_tblTSCollected_tblTSRuleAppliedGOif exists (select * from dbo.sysobjects where id =object_id(N'[dbo].[tblTSCollected]') and OBJECTPROPERTY(id,N'IsUserTable') = 1)drop table [dbo].[tblTSCollected]GOif exists (select * from dbo.sysobjects where id =object_id(N'[dbo].[tblTSRuleApplied]') and OBJECTPROPERTY(id,N'IsUserTable') = 1)drop table [dbo].[tblTSRuleApplied]GOCREATE TABLE [dbo].[tblTSCollected] ([fldCollectedID] [int] IDENTITY (1, 1) NOT NULL ,[fldEmployeeID] [int] NULL ,[fldLocationCode] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_ASNULL ,[fldTimeStamp] [datetime] NULL ,[fldRuleAppliedID] [int] NULL ,[fldBarCode] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,[fldProcessed] [smallint] NOT NULL) ON [PRIMARY]GOCREATE TABLE [dbo].[tblTSRuleApplied] ([fldEmpRuleID] [int] NOT NULL ,[fldRuleAppliedID] [int] IDENTITY (1, 1) NOT NULL ,[fldStartTime] [datetime] NULL ,[fldEndTime] [datetime] NULL ,[fldStartTimeCollectedID] [int] NULL ,[fldEndTimeCollectedID] [int] NULL ,[fldStartArbStatus] [smallint] NULL ,[fldEndArbStatus] [smallint] NULL ,[fldDurationArbStatus] [smallint] NULL ,[fldPrimary] [smallint] NOT NULL ,[fldDateEntered] [datetime] NULL ,[fldEnteredBy] [int] NULL) ON [PRIMARY]GOALTER TABLE [dbo].[tblTSCollected] WITH NOCHECK ADDCONSTRAINT [DF_tblTSCollected_fldProcessed] DEFAULT (0) FOR[fldProcessed],CONSTRAINT [PK_tblTimesheetCollected] PRIMARY KEY CLUSTERED([fldCollectedID]) WITH FILLFACTOR = 90 ON [PRIMARY]GOALTER TABLE [dbo].[tblTSRuleApplied] WITH NOCHECK ADDCONSTRAINT [DF_tblTSRuleApplied_fldPrimary] DEFAULT (1) FOR[fldPrimary],CONSTRAINT [PK_tblTSRuleApplied] PRIMARY KEY CLUSTERED([fldRuleAppliedID]) WITH FILLFACTOR = 90 ON [PRIMARY] ,CONSTRAINT [IX_tblTSRuleApplied_1] UNIQUE NONCLUSTERED([fldStartTimeCollectedID],[fldEndTimeCollectedID]) WITH FILLFACTOR = 90 ON [PRIMARY]GOALTER TABLE [dbo].[tblTSCollected] ADDCONSTRAINT [FK_tblTSCollected_tblEmployee1] FOREIGN KEY([fldEmployeeID]) REFERENCES [dbo].[tblEmployee] ([fldEmployeeID]),CONSTRAINT [FK_tblTSCollected_tblLocation] FOREIGN KEY([fldLocationCode]) REFERENCES [dbo].[tblLocation] ([fldLocationCode]),CONSTRAINT [FK_tblTSCollected_tblTSRuleApplied] FOREIGN KEY([fldRuleAppliedID]) REFERENCES [dbo].[tblTSRuleApplied] ([fldRuleAppliedID])GOALTER TABLE [dbo].[tblTSRuleApplied] ADDCONSTRAINT [FK_tblTSRuleApplied_tblTSCollected] FOREIGN KEY([fldStartTimeCollectedID]) REFERENCES [dbo].[tblTSCollected] ([fldCollectedID]),CONSTRAINT [FK_tblTSRuleApplied_tblTSCollected1] FOREIGN KEY([fldEndTimeCollectedID]) REFERENCES [dbo].[tblTSCollected] ([fldCollectedID]),CONSTRAINT [FK_tblTSRuleApplied_tblTSDurationStatus] FOREIGN KEY([fldDurationArbStatus]) REFERENCES [dbo].[tblTSDurationStatus] ([fldStatus]),CONSTRAINT [FK_tblTSRuleApplied_tblTSEmpRules] FOREIGN KEY([fldEmpRuleID]) REFERENCES [dbo].[tblTSEmpRules] ([fldEmpRuleID]),CONSTRAINT [FK_tblTSRuleApplied_tblTSTimeStatus] FOREIGN KEY([fldStartArbStatus]) REFERENCES [dbo].[tblTSTimeStatus] ([fldStatus]),CONSTRAINT [FK_tblTSRuleApplied_tblTSTimeStatus1] FOREIGN KEY([fldEndArbStatus]) REFERENCES [dbo].[tblTSTimeStatus] ([fldStatus])GO

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Unique Index For Two Columns In A Table

Jul 20, 2005

Hi,I would like to add a unique index that consists of two fields in atable.e.g. tbl_A (field1,field2) -- field1 & field2 Indexed and combinationmust be Unique.Can anyone tell me the actual sql syntax to create this index?Thanks,June.

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Cluster Index On 2 Columns Order

May 29, 2007


I have 2 columns in a table namely ColA and ColB.all DML operations are through views n every view has
Where clause i.e where ColA=€?€? with check option .
All most all my DML queries are using where clause on ColB
Where ColB=€?€?

Now my question is I have a clusted index on both ColA and ColB.in which order I have to create cluster index .
i.e ColA ASC,ColB ASC or ColB ASC,ColA ASC.

Is there any performance gain we can achieve with their order

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Maximum Number Of Columns In An Index

Jun 20, 2007

I am upgrading from Access, where you can only have 10 fields in a primary key or unique index. Is this also the limit in SQL Server? If not, what is the limit?



Thanks for any help on this.

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Create Unique Index On Multiple Columns

Jan 19, 2008

Hello, I will explain myself further. I want to make my table in such a way that no two colums have the same value for example:
Row 1 - Column 1 = "cool"
Row 1 - Column 3 = 91
Row 3 - Column 1 = "cool"
Row 3 - Column 3 = 91
 
I dont care about one column having duplicate values, I want to protect against  Column 1 and 3 having the same values on other rows. Is this possible to do in sql server?

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How To Query Sys Tables For Index Names And Columns

Nov 12, 2001

I'm looking for a query that will return all index names, the table the index is on and the columns in the index...

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SELECT Columns By Column-index NOT By Columnname!

Nov 20, 2005

Hello all,

how can I select one or more columns from a table by column-index and NOT by columnname?

e.g.:

SELECT tbl1.[1], tbl1.[2], tbl1.[3] FROM Orders AS tbl1

and NOT like this:

SELECT tbl1.OrderNo, tbl1.ProductNo, tbl1.Price FROM Orders AS tbl1

Is that possible in MS-SQL 2000?

Thanks a lot in advance

kind regards

Otto

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System SP That Will Retrieve Index Include Columns?

Jan 30, 2008

Hi,

SQL Server 2005 has a new very useful feature for creating non-clustered indexes called INCLUDE <columns> which are very helpful when trying to create covering indexes.

Does anyone know of a way to retrieve these INCLUDE columns through any of the system metadata tables? The sp_helpIndex stored procedure is what I currently use but that only returns the (sorted) index columns and not the include columns.

Thanks in advance,

Gordon Radley

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SQL 2012 :: 5 Columns In Table - Clustered Index Scan

Mar 28, 2014

I have a table with clustered index on that. I have only 5 columns in that table. Execution plan is showing that Index scan occurred. What are the cause of the Index scan how can we change that to index seek?

I am giving that kind of similar query below

SELECT @ProductID= ProductID FROM Product WITH (NOLOCK) WHERE SalesID= '@salesId' and Product = 'Clothes '

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SQL Server 2008 :: Creating Index Including Non-key Columns

Jul 9, 2015

Does including non-key columns work for the performance of an index?

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SQL 2012 :: Creating Index On Multiple Columns Separately

Jul 28, 2015

I used following query to identify missing indexes:

SELECT mid.statement , mid.included_columns, mid.equality_columns, mid.inequality_columns,
migs.avg_total_user_cost * (migs.avg_user_impact / 100.0) * (migs.user_seeks + migs.user_scans) AS improvement_measure,
'CREATE INDEX [NCIX_' + CONVERT (varchar, mig.index_group_handle) + '_' + CONVERT (varchar, mid.index_handle)
+ '_' + LEFT (PARSENAME(mid.statement, 1), 32) + ']'
+ ' ON ' + mid.statement

[Code] ....

I think I need to only create few if an index is covering all columns then I do not need to create more indexes for separate columns or should I create separate index as suggested?

Similarly:

CREATE INDEX [NCIX_20187_20186_TL_SRV_Stationary_Stock_Transact] ON [TL_SRV_Stationary_Stock_Transaction] ([SerialNo],[StationaryStatus]) GO
CREATE INDEX [NCIX_20189_20188_TL_SRV_Stationary_Stock_Transact] ON [TL_SRV_Stationary_Stock_Transaction] ([StationaryStatus]) INCLUDE ([SerialNo]) GO

[Code] ....

Should I create all indexes above or use minimum number of indexes which covers all columns as mentioned in above create index statements?

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Index Was Outside The Bounds Of The Array - When Table Columns Deleted

Aug 14, 2007



Hi

If I delete 5 or more columns from a table I get the error "Index was outside the bounds of the array", OK is the only response. I then have to close the report and then open it again.

Easy fix is don't delete more than 5 columns, but my template is setup with 15 columns as it's far quicker to delete them as it is to add them 1 by 1 each time. I've finally got around to looking for a hotfix or something similar but can find no mention of this exact error relating to table column deleting.

Anyone else experience this or know if there is a hotfix for it?


Thanks

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SQL 2012 :: Include Columns In Index That Are In Where Clause / Select List And Join

Jun 2, 2014

Usually it is better to include the columns in the index that are in where clause, select list and join.I am thinking that the columns in the selected list is better to keep as index columns and the columns that are in the where clause is better to keep in key columns.Where do we use join column is it better to create as main key column or included column.

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SQL Server 2014 :: Find Views Which Has More Than 16 Columns For Unique Index / Constraint

Oct 27, 2015

We are on SQL 2014...we have a bunch of views in a database where we are trying to find the views which have more than 16 columns max for unique index/constraint...this is needed so we can convert them to indexed views...

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Multiple Columns Index/Key (does It Free Me From Creating A Single Column Indexes???)

Apr 12, 2007

I hope i'm in the right place, but thanks anyway....

Actually i have 2 questions (regarding sql-server Indices/Keys):



1) I have an index, which is consisted of 4 columns.

I've read elsewhere that this index functions (as well) as an index (single column

index) on the first column of this multi-column index.



Does this mean that if i'd like to have (in addition) Indices on all of the 4 columns

seperately i need to define only 3???



2) I have a unique key consisted of multiple columns.

I'd like to save an index to this combination of columns as well (to speed up

things in DB...).

Does the definition of a multiple-columns key free me from defining the multiple-

columns index???

can anyone explain the main diference between Keys and Indices???





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Multiple Columns Index/Key (does It Free Me From Creating A Single Column Indexes???)

Apr 16, 2007

I hope i'm in the right place, but thanks anyway....

Actually i have 2 questions (regarding sql-server Indices/Keys):



1) I have an index, which is consisted of 4 columns.

I've read elsewhere that this index functions (as well) as an index (single column

index) on the first column of this multi-column index.



Does this mean that if i'd like to have (in addition) Indices on all of the 4 columns

seperately i need to define only 3???



2) I have a unique key consisted of multiple columns.

I'd like to save an index to this combination of columns as well (to speed up

things in DB...).

Does the definition of a multiple-columns key free me from defining the multiple-

columns index???

can anyone explain the main diference between Keys and Indices???


thanks,

Ran Kizi

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Sep 16, 2015

In SQL 2012.A query that joins 2 table, with order by clause doesn't get sorted and the result set is not ordered. This happens when some of the columns in the where criteria are in a unique index which is the index that is used for the join between the 2 tables, and all the columns in the unique index are in the where criteria.In the query plan there is no component for sort.The work around was to drop the unique index, or change it to a non-unique index. Once this was done, the execution plan was changed to add the sort component (even when the index was changed to non-unique and the join was still using this index).

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Transact SQL :: Any Reason For Difference In Order Of Columns Between Index Of Constraint And Its Statistics Definition?

Sep 5, 2015

I am really puzzled by an apparent difference between table index key column order and its statistics order. I was under understanding that index statistics mirror index definition. However, in my db 2470 index ordinal definitions match statistics definition but 66 do not. I also can reproduce such discrepancy in 2008 R2, 2012 and 2014.

As per definition,

stats_column_id
int

1-based ordinal within set of stats columns

This script duplicates this for me.

BEGIN TRAN
GO
use tempdb
GO
CREATE TABLE [dbo].[ItemProperties](
[itmID] [int] NOT NULL,
[cpID] [smallint] NOT NULL,
[ipuID] [tinyint] NOT NULL,

[Code] ....

The result I get is this:

object_id       stats_name                                     
stats_column_list
1525580473 PK_ItemProperties_itmID_ipuID_cpID itmID,  cpID,  ipuID,

and

object_id      index_name                                     
index_column_list
1525580473 PK_ItemProperties_itmID_ipuID_cpID itmID,  ipuID,  cpID,

Also a query I used to discover this in my db is:

WITH stat AS
(
SELECT
s.object_id
,s.name as stats_name
,(
SELECT
c.name + ', ' as [data()]
FROM sys.stats_columns as sc

[Code] .....

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Oct 20, 2006

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thank you in advance

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Apr 14, 2008

For example: we have 2 set {1,4,8}, {1,2,3,4,5,8,9,0}

Is there any other fast way to decide {1,4,8} is in cluded in {1,2,3,4,5,8,9,0} ?
beside loop, or insert them into two table then check not exists?

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Database Is Not Valid To Be Included In...

Jan 28, 2008

Hi folks

I've just set up a maintenance plan that backs up all user databases daily and logs hourly. I've just noticed that the plan history is giving the following error -

Database 'BizTalkEDIDb' is not valid to be included in the maintenance plan.

Has anyone seen this before or know how to resolve it?

James

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