difference between select single and select up to 1 rows

[Former Member]

Hi all i have a doubt : difference between select single and select up to 1 rows in select statement.

thanks in advance

Jana

[Former Member]

Hi Janajana,

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.

You can refer to the below link..

http://www.sap-img.com/abap/difference-between-select-single-and-select-upto-one-rows.htm

regards,

amit m.

[former_member181962]

slect single gets the unique record for a where clause.

select up to gets the first of available ones.

select single expects all the key fields to be passed.

select up to doesn't need all the keys.

Regards,

Ravi

[rahulkavuri]

Select upto 1 row does not require any WHERE condition

Select single * requires WHERE condition

Select single * picks one of the matching records but select upto 1 row picks the first matching record

[Former Member]

same thread..

[former_member927251]

Hi,

<b>Refer the following link and reward points if it helps.</b>

http://www.sapsuperusers.com/forums/showthread.php?t=4867

[Former Member]

<b>Select Single</b>

You need to mention all the key fields of the table.

No END SELECT required.

More performance compared to upto 1 row.

<b>Where as UP to 1 row.</b>

YOu can use if you do not have all the primiary key fields available.

END SELECT requeired.

Since all keys are not passing, possiblities of have other rows which satisfies the condition.

Cheers,

Thomas.

Please reward points if you got the answer

[Former Member]

hii Kumar ,

Select Statement with EndSelect is a loop, which in a single run retrieves a single Record. This Record has to be stored in a Work Area and then appended into an Internal Table.

Select Statements without EndSelect is not a loop and it retrieves the whole Record set matching the Criteria in a single shot and has to be Stored in an Internal Table Directly.

The most important thing to remember about the SELECT SINGLE is

There are several things to remember:

1) <b>It retrieves only one row

2) It does not need an ENDSELECT statement

3) THE FULL KEY OF THE TABLE MUST BE INCLUDED IN

THE WHERE CLAUSE OF THE SELECT STATEMENT</b>

[Former Member]

Hi,

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.

You can refer to the below link:-

http://www.sap-img.com/abap/difference-between-select-single-and-select-upto-one-rows.htm

Please reward points if helpful.

Thanks,

Ramya.