10-25-2007 11:09 AM
Dear All,
I want to optimise the Code performance.
I don't have full table key. So, what is better to use - SELECT SINGLE or SELECT UPTO 1 ROW?
Please ASAP.
Thanks in advance.
Prasad.
10-25-2007 11:10 AM
10-25-2007 11:14 AM
Hi Prasad,
Whenever you havan index its better to Use SELECT SINGLE.
In Your case , You can use SELECT UPTO 1 Row.
Reward if Useful.
Regards,
Chitra
10-25-2007 11:14 AM
10-25-2007 11:15 AM
According to SAP Performance course the SELECT UP TO 1 ROWS is faster than SELECT SINGLE because you are not using all the primary key fields.
select single is a construct designed to read database records with primary key. In the absence of the primary key, it might end up doing a sequential search, whereas the select up to 1 rows may assume that there is no primary key supplied and will try to find most suitable index.
The best way to find out is through sql trace or runtime analysis.
Use "select up to 1 rows" only if you are sure that all the records returned will have the same value for the field(s) you are interested in. If not, you will be reading only the first record which matches the criteria, but may be the second or the third record has the value you are looking for.
The System test result showed that the variant Single * takes less time than Up to 1 rows as there is an additional level for COUNT STOP KEY for SELECT ENDSELECT UP TO 1 ROWS.
The 'SELECT SINGLE' statement selects the first row in the database that it finds that fulfils the 'WHERE' clause If this results in multiple records then only the first one will be returned and therefore may not be unique.
Mainly: to read data from
The 'SELECT .... UP TO 1 ROWS' statement is subtly different. The database selects all of the relevant records that are defined by the WHERE clause, applies any aggregate, ordering or grouping functions to them and then returns the first record of the result set.
Mainly: to check if entries exist.
10-25-2007 11:16 AM
Hi ,
Difference Between Select Single and Select UpTo One Rows
According to SAP Performance course the SELECT UP TO 1 ROWS is faster than SELECT SINGLE because you are not using all the primary key fields.
select single is a construct designed to read database records with primary key. In the absence of the primary key, it might end up doing a sequential search, whereas the select up to 1 rows may assume that there is no primary key supplied and will try to find most suitable index.
The best way to find out is through sql trace or runtime analysis.
Use "select up to 1 rows" only if you are sure that all the records returned will have the same value for the field(s) you are interested in. If not, you will be reading only the first record which matches the criteria, but may be the second or the third record has the value you are looking for.
The System test result showed that the variant Single * takes less time than Up to 1 rows as there is an additional level for COUNT STOP KEY for SELECT ENDSELECT UP TO 1 ROWS.
The 'SELECT SINGLE' statement selects the first row in the database that it finds that fulfils the 'WHERE' clause If this results in multiple records then only the first one will be returned and therefore may not be unique.
Mainly: to read data from
The 'SELECT .... UP TO 1 ROWS' statement is subtly different. The database selects all of the relevant records that are defined by the WHERE clause, applies any aggregate, ordering or grouping functions to them and then returns the first record of the result set.
Mainly: to check if entries exist.
Regards
ANJI
10-25-2007 11:20 AM
hi,
source:Prashant Patil
Re: select upto 1 row & select single *
Posted: Jul 17, 2006 6:33 AM in response to: fsdf sdf
According to SAP Performance course the SELECT UP TO 1 ROWS is faster than SELECT SINGLE because you are not using all the primary key fields.
select single is a construct designed to read database records with primary key. In the absence of the primary key, it might end up doing a sequential search, whereas the select up to 1 rows may assume that there is no primary key supplied and will try to find most suitable index.
Use "select up to 1 rows" only if you are sure that all the records returned will have the same value for the field(s) you are interested in. If not, you will be reading only the first record which matches the criteria, but may be the second or the third record has the value you are looking for.
The System test result showed that the variant Single * takes less time than Up to 1 rows as there is an additional level for COUNT STOP KEY for SELECT ENDSELECT UP TO 1 ROWS.
The 'SELECT SINGLE' statement selects the first row in the database that it finds that fulfils the 'WHERE' clause If this results in multiple records then only the first one will be returned and therefore may not be unique.
Mainly: to read data from
The 'SELECT .... UP TO 1 ROWS' statement is subtly different. The database selects all of the relevant records that are defined by the WHERE clause, applies any aggregate, ordering or grouping functions to them and then returns the first record of the result set.
10-25-2007 11:21 AM
Hi,
upto 1 row is faster in this case.
<b>
reward points if useful.</b>
regards,
Vinod Samuel.
10-25-2007 11:23 AM
hi,
"SELECT SINGLE" always gives good performance.
May i know which table you are using.
Senthil kumar
10-25-2007 11:26 AM
hi,
when u have all primary keys for u to select or index then go for select single * otherwise use select upto n rows statement.
try with ST02, SE30 T.codes.
if helpful reward some points.
with regards,
Suresh Aluri.
10-25-2007 11:30 AM
hi prasad,
in case u don't have the full table key it's better to use SELECT....UP TO 1 ROWS...SELECT SINGLE is used only in cases you have the full table key..
regards,
Vitish
03-10-2011 3:07 PM