topic Re: Select Single in Application Development and Automation Discussions

Select Single

Former Member — Wed, 11 Oct 2006 13:23:10 GMT

Hi Gyes,

What is the difference between <b>Select Single</b> and <b>Select Upto 1 Row</b>.

Re: Select Single

Former Member — Wed, 11 Oct 2006 13:25:57 GMT

hi Suresh,

difference between select single and select up to 1 row

Regards,

santosh

Re: Select Single

vadrevu_kk — Wed, 11 Oct 2006 13:26:39 GMT

We are using select single if u have all primary keys. then it is very for good for performance. Otherwise we willuse select upto one row.

Regards.

Kiran

Re: Select Single

Former Member — Wed, 11 Oct 2006 13:28:04 GMT

Re: Select Single

Former Member — Wed, 11 Oct 2006 13:58:15 GMT

Hi,

select single aand select upto 1 rows return 1 rows

but select single is used when we have all keys

in where clause

select matnr from marc where matnr = p_matnr

and werks = p_werks.

else

select upto 1 row is used if we dont have all keys

in where clause

select matnr from marc upto 1 rows where matnr =

p_matnr

endselect.

performance wise select single is optimum.

Regards,

Amole

Re: Select Single

anversha_s — Wed, 11 Oct 2006 14:05:05 GMT

hi suresh,

chk this.

ex code

***********

Report Z_Difference

Message-id 38

Line-Size 80

Line-Count 0

No Standard Page Heading.

Start-Of-Selection.

Data: w_Single type Posnr,

t_Rows type standard table of Posnr

initial size 0

with header line.

Select single Posnr

from zDifference

into w_Single.

Select Posnr

into table t_Rows

from zDifference

up to 1 rows

order by Posnr descending.

Write 😕 'Select single:', w_Single.

Skip 1.

Write 😕 'Up to 1 rows :'.

Loop at t_Rows.

Write t_Rows.

EndLoop.

*******************************************

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

rgds

anver

pls mark points if helpful

Re: Select Single

former_member404244 — Wed, 11 Oct 2006 14:41:35 GMT

Hi suresh,

select single and select upto 1 rows are having their roles.

if u r retrieving the data using primary key then go for select single and give the entire primary key information.

If u r retrieving the data without primary key then go for select upto 1 rows will be a better option.

For select single u dont have to use endselect,but for upto 1 rows u should use endselect.

for example..

select single matnr from mara into v_mara

where = ;;;.

select matnr from mara into v_mara

upto 1 rows where =;;;

endselect.

Regards,

Nagaraj