topic Re: select statement in Application Development and Automation Discussions

select statement

Former Member — Fri, 06 Jul 2007 08:41:30 GMT

hi,

can anybody tell me what is the diffrence between

SELECT SINGLE * FROM and UP TP 1 ROWS.

Re: select statement

Former Member — Fri, 06 Jul 2007 08:43:42 GMT

Hi KIran

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.

Reward all helpfull answers

Regards

Pavan

Re: select statement

PS_1978 — Fri, 06 Jul 2007 08:46:23 GMT

Hi Kiran,

select single extracts only one record from the data base table based on the primary keys. The pre requisite for using select single is the select statement must be having all the primary keys in the where clause. It also suggestable considering the performance point of view.

where as select up to 1 rows can be used when there is no provision to use all the primary keys in the where clause of the select statement. It also extracts only one record from the data base table based on the where clause.

Regards,

Phani.

Re: select statement

Former Member — Fri, 06 Jul 2007 08:46:57 GMT

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.

The best way to find out is through sql trace or runtime analysis.

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.

Mainly: to read data from

Mainly: to check if entries exist.

Reward points for useful Answers

Regards

Anji

Re: select statement

Former Member — Fri, 06 Jul 2007 08:48:43 GMT

Hi,

Kiran, SELECT SINGLE * should be used and should be given priority for usage as it is very efficient when comparing with the usage of SELECT ... UPTO 1 ROWS.

But if you are going to perform any aggregations in the select statement you cannot be using SELECT SINGLE. So at that point of time you need to use the other option.

Reward points if this helps,

Kiran

Re: select statement

Former Member — Fri, 06 Jul 2007 08:48:45 GMT

Hi,

The Select single ITSELF IS USED TO RETRIVE ONE RECORD FROM DATABASE.F YOU KNOW THE PRIMARY KEY OF THE RECORD YOU WISH TO RETRIEVE,SELECT SINGLE IS MUCH FASTER THAN SELECT/ENDSELECT.

i THINK NO NEED OF SPECIFING THE UPTO 1 ROWS

Reward if helpful

Regrads

Raghavendra.D.S

Re: select statement

Former Member — Fri, 06 Jul 2007 08:49:17 GMT

Hi Kiran,

In simple words Both will be used to fetch one record from DB,..

First is used when you have the full key of the DB table in WHERE clause

Second is used when you don't have the full key.

Regards,

Atish

Re: select statement

Former Member — Fri, 06 Jul 2007 08:54:58 GMT

HI.

Select single * from KNA1 where clause

---It fetches single record from the database, based on the condition you specified in the where clause.

Where as select * from kna1 up to 1 row

---Fetches first record if the condition specified in the where clause is satisfied, otherwise it doesn't fetch any record.

Reward all helpfull answers.

Regards.

Jay

Re: select statement

mohammed_moqeeth — Fri, 06 Jul 2007 08:56:00 GMT

Hi Kiran,

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.

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 or lack of, applies any aggregate, ordering or grouping functions to them and then returns the first record of the resultant result set.

chec the below link for Difference between select single and up to 1 row

SELECT SINGLE*:

The result of the selection should be a single entry. If it is not possible to identify a unique entry, the system uses the first line of the selection.

Here is a reference program for you:

DATA wa TYPE spfli.

SELECT SINGLE * FROM sflight INTO wa

WHERE

carrid = 'LH ' AND

connid = '0400' AND

fldate = '20010228'.

FLDATE = '19950228'.

WRITE: / wa-carrid, wa-connid, wa-fldate, seatsfree.

SELECT SINGLE:

Selecting the required fields,instead of selcting all the fields

TYPES:begin of itab,

carrid type sflight-carrid,

connid type sflight-connid,

fldate type sflight-fldate,

seatsfree type sflight-seatsfree,

end of itab.

data:wa type itab.

SELECT SINGLE carrid connid fldate seatsfree FROM sflight INTO wa

WHERE

carrid = 'LH ' AND

connid = '0400' AND

fldate = '20010228'.

FLDATE = '19950228'.

WRITE: / wa-carrid, wa-connid, wa-fldate, seatsfree.

find the below link for your kind reference:

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

Reward points foe every useful answers........

Cheers !

Moqeeth.

Re: select statement

Former Member — Fri, 06 Jul 2007 09:07:28 GMT

The big idea of using UP TO 1 ROWS instead of SELECT SINGLE is that you can control which record you receive by specifying ORDER BY.

Example:

SELECT * FROM anytable UP TO 1 ROWS

WHERE tablevalue = myvalue

ORDER BY date DESCENDING.

In this case you get the record with the highest date.

With SELECT SINGLE the result would be arbitrary among the records chosen by the WHERE clause.

Regards

Poul Bundgaard

Re: select statement

Former Member — Fri, 06 Jul 2007 09:22:15 GMT

Hi,

SELECT SINGLE * FROM : means u are going to fetch and display only single record for the given table from the database into buffer memory.

UP TO 1 ROWS : means u are going to fetch the entire table but display only single record for the given table from the database into buffer memory.

Pls reward points.

Regards,

Ameet

Re: select statement

Former Member — Fri, 06 Jul 2007 09:27:10 GMT

Hi kiran,

Select single selects single entry but up to one row select only 1st row selection.

it is faster than select single