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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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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Aug 14, 2007
Hi,Would like to know the performance differenece between Multi-columnIndex vs Single Column Indexes. Let's say I have a table with col1,col2, col3 along with a primary key column and non-indexed columns.In queries, I will use col1, col2, and col3 together and some timesjust one or two of these three columns. My questions is, should Icreate one index contains col1, col2, and col3, or create 3 seperatedcolumns. I.e. each column has its own index. Any performancedifference?Thanks a lot.
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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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Mar 3, 2008
Please can anyone help me for the following?
I want to merge multiple rows (eg. 3rows) into a single row with multip columns.
for eg:
data
Date Shift Reading
01-MAR-08 1 879.880
01-MAR-08 2 854.858
01-MAR-08 3 833.836
02-MAR-08 1 809.810
02-MAR-08 2 785.784
02-MAR-08 3 761.760
i want output for the above as:
Date Shift1 Shift2 Shift3
01-MAR-08 879.880 854.858 833.836
02-MAR-08 809.810 785.784 761.760
Please help me.
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Aug 22, 2007
Hi,
I have multiple columns in a Single Table and i want to search values in different columns. My table structure is
col1 (identity PK)
col2 (varchar(max))
col3 (varchar(max))
I have created a single FULLTEXT on col2 & col3.
suppose i want to search col2='engine' and col3='toyota' i write query as
SELECT
TBL.col2,TBL.col3
FROM
TBL
INNER JOIN
CONTAINSTABLE(TBL,col2,'engine') TBL1
ON
TBL.col1=TBL1.[key]
INNER JOIN
CONTAINSTABLE(TBL,col3,'toyota') TBL2
ON
TBL.col1=TBL2.[key]
Every thing works well if database is small. But now i have 20 million records in my database. Taking an exmaple there are 5million record with col2='engine' and only 1 record with col3='toyota', it take substantial time to find 1 record.
I was thinking this i can address this issue if i merge both columns in a Single column, but i cannot figure out what format i save it in single column that i can use query to extract correct information.
for e.g.;
i was thinking to concatinate both fields like
col4= ABengineBA + ABBToyotaBBA
and in search i use
SELECT
TBL.col4
FROM
TBL
INNER JOIN
CONTAINSTABLE(TBL,col4,' "ABengineBA" AND "ABBToyotaBBA"') TBL1
ON
TBL.col1=TBL1.[key]
Result = 1 row
But it don't work in following scenario
col4= ABengineBA + ABBCorola ToyotaBBA
SELECT
TBL.col4
FROM
TBL
INNER JOIN
CONTAINSTABLE(TBL,col4,' "ABengineBA" AND "ABB*ToyotaBBA"') TBL1
ON
TBL.col1=TBL1.[key]
Result=0 Row
Any idea how i can write second query to get result?
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Mar 4, 2008
I have a table which has single column like this.
REP5426 02-28-08 0592 00100028 CAFE 00205415 23.77 A O INPUT
REP5426 02-28-08 0592 00100028 CAFE 00580910 475.58 A O INPUT
REP5426 02-28-08 0592 00100028 CAFE 00800840 -13.32 A O INPUT
REP5426 02-28-08 0592 00100028 CAFE 00205416 23.77 A O INPUT
I want to put this in a new table in individual columns
Col1 col2 col3 col4 col5 col6 col7 col8 col9
REP5426 02-28-08 0592 00100028 CAFE 00205415 23.77 A O INPUT
REP5426 02-28-08 0592 00100028 CAFE 00580910 475.58 A O INPUT
REP5426 02-28-08 0592 00100028 CAFE 00800840 -13.32 A O INPUT
REP5426 02-28-08 0592 00100028 CAFE 00205416 23.77 A O INPUT
How to do this.
Thanks.
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Jun 4, 2015
I have a requirements to make a single column using a date from multiple columns. below my DDL and sample.
Create table #Mainsample
(ItemNum nvarchar(35), ItemDate datetime, OPType int)
Insert into #Mainsample(ItemNum,ItemDate, OPType) values ('M9000000000020510095','2015-05-01 18:38:48.840',5)
Insert into #Mainsample(ItemNum,ItemDate, OPType) values ('M9000000000020510094','2015-05-02 20:38:40.850',5)
Insert into #Mainsample(ItemNum,ItemDate, OPType) values ('M9000000000020510092','2015-05-02 21:40:42.830',5)
Insert into #Mainsample(ItemNum,ItemDate, OPType) values ('353852061764483','2015-05-02 09:25:10.800',5)
[code]....
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Mar 9, 2008
I have FirstName,LastName columns in the database.I need to return FirstName,LastName as Name to client(as a single column).
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Oct 8, 2007
Suppose that I have a table with following values
Table1
Col1 Col2 Col3
-----------------------------------------------------------
P3456 C935876 T675
P5555 C678909 T8888
And the outcome that I want is:
CombinedValues(ColumnName)
----------------------------------------------
P3456 - C935876 - T675
P5555 - C678909 - T8888
where CombinedValues column contains values of coulmn 1,2 & 3 seperated by '-'
So is there any way to achieve this?
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Mar 3, 2015
I have a description field in a table which also stores unit of measure in the same column but with some space between them, I need to split these into two different columns.
For Eg:
Description
APPEARANCE UNIT
BDV KV
DENSITY KG/L
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Oct 19, 2015
I'm working on a script to merge multiple columns(30) into a single column separated by a semicolons, but I'm getting the following error below. I tried to convert to the correct value. but I'm still getting an error.
Error: "Conversion failed when converting the varchar value ';' to data type tinyint".
select
t1.Code1TypeId + ';' +
t1.Code2TypeId + ';' +
t1.Code3TypeId + ';' +
t1.Code4TypeId as CodeCombined
from Sampling.dbo.account_test t1
where t1.Code1TypeId = 20
or t1.Code2TypeId = 20
or t1.Code3TypeId = 20
or t1.Code4TypeId = 20
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Apr 21, 2015
I have a table with single row like below
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Column0 | Column1 | Column2 | Column3 | Column4|
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Value0 | Value1 | Value2 | Value3 | Value4 |
Am looking for a query to convert above table data to multiple rows having column name and its value in each row as shown below
_ _ _ _ _ _ _ _
Column0 | Value0
_ _ _ _ _ _ _ _
Column1 | Value1
_ _ _ _ _ _ _ _
Column2 | Value2
_ _ _ _ _ _ _ _
Column3 | Value3
_ _ _ _ _ _ _ _
Column4 | Value4
_ _ _ _ _ _ _ _
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Apr 3, 2002
I have a database where records are Inserted by an external process.
There is no updating or deleting of the data once inserted. The table in
question has a Clustered Index on the Machine_ID (integer) (data is from
manufacturing processes). Each record bears a start and end time. Most
queries involve the Machine, a time span (start time between to points in
time), the Downtime Cause, and the Running Mode.
I want to add an index on the Start Time, the Downtime Cause, and the
Runtime Mode.
My question is: should this new index also contain the Machine_id column
or does the existence of the Clustered Index already on that column negate
its need in the new index?
RC - Dedicated to only creating original mistakes!
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Apr 3, 2015
I've been asked to look at using Clustered Columnstore indexes for one of my tables. The table contains about 5 million records with about 50 columns. The max field size is a NVarchar(MAX) with max field length currently of about 4k characters. It's only about a gigabyte's worth of data. The table is about 50% R/W operations. Currently, we have multiple indexes with no clustered index due to some performance issues that happened in the past. I've been attempting to determine if it's even really worth it to switch over. I feel that the table is still fairly small with minimal columns and don't believe there will be any noticeable improvement over traditional indexing.
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Nov 9, 2006
Hi,
I want to create two databases by restoring from a
single backup file in sql server. I am using 2005-sqlexpress .Is it possible?
Thanx in advance..
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Jul 9, 2015
Does including non-key columns work for the performance of an index?
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Jan 21, 2008
Hi All
I have a table with indexes as follows
license_detail_prim
clustered, unique located on PRIMARY
component_id, license_id
LICENSE_DTL_IDX_LICENSE_ID
nonclustered located on PRIMARY
license_id
PK__license_dtl__6EB64F9B
nonclustered, unique, primary key located on PRIMARY
component_id, license_id
XIF39license_dtl
nonclustered located on PRIMARY
license_id
from the above, it is evident that multiple indexes have been created on the same columns
What is the side effects of havins such table design.
Thanks
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Jun 15, 2006
Hi. I want to return multiple rows into a single row in different columns. For example my query returns something like thisThe query looks like thisSelect ID, TYPE, VALUE From myTable Where filtercondition = 1ID TYPE VALUE1 type1 121 type2 152 type1 16 2 type2 19Each ID will have the same number of types and each type for each ID might have a different value. So if there are only two types then each ID will have two types. Now I want to write the query in such a way that it returnsID TYPE1 TYPE2 VALUE1 VALUE21 type1 type2 12 152 type1 type2 16 19Type1, Type2, Value1, and Value2 are all dynamic. Can someone help me please. Thank you.
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Mar 31, 2008
Running SQL2000
I have a one to many relationship between Flag and StudentFlag. I'm wanting to select each Flag.FlagID that exist as a column that contains the StudentFlag.Value per StudentFlag.StudentID (or null for that column if that StudentFlag row doesn't exist).
This single column appearing multple times in a single dataset has seemed difficult in a select statement. Is it posible in T-SQL?
Tables, Keys, and Relationships
CREATE TABLE [dbo].[Flag] (
[FlagID] [int] NOT NULL ,
[FlagName] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[StudentFlag] (
[StudentFlagID] [int] NOT NULL ,
[FlagID] [int] NULL ,
[StudentID] [int] NOT NULL ,
[FlagValue] [varchar] (50) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[Flag] WITH NOCHECK ADD
CONSTRAINT [PK_Flag] PRIMARY KEY CLUSTERED
(
[FlagID]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[StudentFlag] WITH NOCHECK ADD
CONSTRAINT [PK_StudentFlag] PRIMARY KEY CLUSTERED
(
[StudentFlagID]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[StudentFlag] ADD
CONSTRAINT [FK_StudentFlag_Flag] FOREIGN KEY
(
[FlagID]
) REFERENCES [dbo].[Flag] (
[FlagID]
)
GO
Sample Output
StudentID, FlagType1, FlagType2, FlagType3
1, 'yes', '2', null
2, null, null, 'X'
3, null, '7', 'X'
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Apr 15, 2008
Hi all,
My code below creates a trigger that fires whenever a change occurs to a 'myTable' row, but this is not what I want. I only want to log changes made to a single field called 'Charges', when that field is changed I want to log it, can anyone tell me how to modify my code to do this, thanks
Create Trigger dbo.myTrigger
ON dbo.[myTable]
FOR UPDATE
AS
Declare @now DATETIME
Set @now = getdate()
BEGIN TRY
Insert INTO dbo.myAuditTable
(RowImage,Charges,ChangeDate,ChangeUser)
SELECT 'BEFORE',Charges,@now, suser_sname()
FROM DELETED
Insert INTO dbo.myAuditTable
(RowImage,Charges,ChangeDate,ChangeUser)
SELECT 'AFTER',Charges,@now, suser_sname()
FROM INSERTED
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION
END CATCH
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Apr 25, 2014
I have this query
SELECT
'Type'[Type]
,CASE WHEN code='09' THEN SUM(Amt/100) ELSE 0 END
,CASE WHEN code='10' THEN SUM(Amt/100) ELSE 0 END
,CASE WHEN code='11' THEN SUM(Amt/100) ELSE 0 END
,CASE WHEN code='12' THEN SUM(Amt/100) ELSE 0 END
FROM Table1 WHERE (Code BETWEEN '09' AND '12')
GROUP BY Code
and the output
Column 1 Column 2 Column 3 Column 4
Type 14022731.60 0.00 0.00 0.00
Type 0.00 4749072.19 0.00 0.00
Type 0.00 0.00 149214.04 0.00
Type 0.00 0.00 0.00 792210.10
How can I modify the query to come up with output below,
Column 1 Column 2 Column 3 Column 4
Type 14022731.60 4749072.19 149214.04 792210.10
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Jul 16, 2014
what the best practice is for creating indexes on columns that are foreign keys to the primary keys of other tables. For example:
[Schools] [Students]
---------------- -----------------
| SchoolId PK|<-. | StudentId PK|
| SchoolName | '--| SchoolId |
---------------- | StudentName |
-----------------
The foreign key above is as:
ALTER TABLE [Students] WITH CHECK ADD CONSTRAINT [FK_Students_Schools]
FOREIGN KEY([SchoolId]) REFERENCES [Schools] ([SchoolId])
What kind of index would ensure best performance for INSERTs/UPDATEs, so that SQL Server can most efficiently check the FK constraints? Would it be simply:
CREATE INDEX IX_Students_SchlId ON Students (SchoolId)
Or
CREATE INDEX IX_Students_SchlId ON Students (SchoolId, StudentId)
In other words, what's best practice for adding an index which best supports a Foreign Key constraint?
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Feb 27, 2008
Hello,
I need to concatenate a column from multiple rows into a single column in a new table.
How can I do this?
SID NAME PGROUP
------------------------------------------------------------
3467602 CLOTHINGACTIVE
3467602 CLOTHINGDANCE
3467602 CLOTHINGLWR
Need to have
SID NAME PGROUP
------------------------------------------------------------
34676 02 CLOTHING ACTIVE , DANCE, LWR
THANK YOU
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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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Jan 13, 2015
I have multiple databases in the server and all my databases have tables: stdVersions, stdChangeLog. The stdVersions table have field called DatabaseVersion which stored the version of the database. The stdChangeLog table have a field called ChangedOn which stored the date of any change made in the database.
I need to write a query/stored procedure/function that will return all the database names, version and the date changed on. The results should look something like this:
DatabaseName DatabaseVersion DateChangedOn
OK5_AAGLASS 5.10.1.2 2015/01/12
OK5_SHOPRITE 5.9.1.6 2015/01/10
OK5_SALDANHA 5.10.1.2 2014/12/23
The results should be ordered by DateChangedOn.
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Jul 1, 2014
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?
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Sep 10, 2014
I’m trying to figure out a way to sum columns for similar IDs, based on the contents of a single field. For example, if I’m calculating attendance percentages for students, and codes P and T count as Present, and codes A and E count as Absent, I would want to total Present and Absent codes separately, in their own columns. I would then like to use those totals to calculate percentage, but I can do that. It’s the SUM based on column value (by ID) that is giving issue.
If I have the following view:
IDLNFNCDTotal
123456MearsBenP12
123456MearsBenA2
123456MearsBenT6
234567NortonSusanP15
234567NortonSusanA2
234567NortonSusanT2
234567NortonSusanE1
I would like something like this:
IDLNFNPresentAbsentPercentage
123456MearsBen18290.0
234567NortonSusan17385.0
I’ve been playing around with nested queries, but nothing’s working. This is a glimpse of the mess that I’ve created trying to sort this out. Many errors.
I just noticed that I used a simpler example than the SQL I included, so I modified it a bit. There are additional fields that I'll need to include, but I want to get the logic working correctly. From there, I can handle the rest. So here's a more appropriate code example showing the direction I'm trying to go with this.
SELECT ID, [Last Name], [First Name], CD, Present, Absent, CAST(LEFT(Present / (Absent + Present) * 100, 5) AS varchar) + '%' AS Percentage
FROM (SELECT ID, CD, TotalAHD, CAST
((SELECT SUM(TotalAHD) AS Expr1
FROM SumAHDforAttndPercentages AS p
[Code] ...
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Dec 24, 2014
I have 5 million rows of table, and going to create Non Clustered Index for Datetime values column. Creating Non clustered Index on Datetime value column will affect performance or not.
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Jul 28, 2015
So I have a problem with combining cells: some of the cells are blank and some of the cells have NULL value.
The combined blank cells return perfect.
But the combined cells in which 1 or more contains NULL will return as NULL
0-4139-00-01OPTIONAL EQUIPMENT 139 - A -
0-4139-00-02NVG EQUIPMENT 139 - A -
0-4139-00-03NVG EQUIPMENT 139 - A -
0139-01-01BRAKE RESERVOIR NULL
A part of the script which i use is:
STUFF((SELECT ', ' + i.ac_type + ' - '
+ i.range_or_single+ ' ' + ' - ' + i.serialno_to
FROM msc_item_effectivity i
inner JOINmsc_item h
ONb.taskcard_verno_i = h.taskcard_verno_i
WHERE h.itemno_i = i.itemno_i
FOR XML PATH('')), 1, 1, '')
i.ac_type = 139
i.range_or_single = A
i.serialno_to = blank or NULL
I want the result of the blank value to be the same as the NULL value.
0139-01-01BRAKE RESERVOIR 139 - A -
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Dec 19, 2006
Hi:
I have a data flow task in which there is a OLEDB source, derived column item, and a oledb destination. My source is a SQL command, that returns some values. I have some values, that I define in the derived columns, and set default values under the expression column. My question is, I also have some destination columns which in my OLEDB destination need another SQL command. How would I do that? Can I attach two or more OLEDB sources to one destination? How would I accomplish that? Thanks
MA2005
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Jan 13, 2005
Hi
This is probably a very basic question for most people in this group.
How do i split the data in a column in to 2 columns? This can be done in access with an update query but in MS SQL server I am not sure.
Here is an example of what i want to acheive
FName
John?Doe
FName LName
John Doe
thanks for the help
prit
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May 25, 2015
Somewhere i read..that in SQL Server...usage of Built-in Functions on Columns, makes query optimizer to ignore indexes on that column...!
So lets say we have table EMP with Emp_id and Emp_Name....
Also we have Non-Clustered index on Emp_Name.
So following query would NOT use Non-Clustered index on Emp_Name column.
SELECTLEFT(emp_name, 3) as emp3
FROMdbo.EMP
Is this true? i am using SQL Server 2008.
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