Regarding Select querry

[Former Member]

Hi Experts,

Can you please explain the exact difference b/n Select Single and select upto 1 row...

Thankx in Advance..

Shobha Henry..

[p291102]

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.

Thanks,

Shankar

[Former Member]

Hi,

Select single will fetch the exact one record which will match the where copndition.

We use the key fields in the where condition for it.No endselect is required.

Up to 1 rows fetch one of the record that will match the where condition from the table. Enselect is required. generally when key fields are not used in where condn we use this.

Regards,

Anji

[Former Member]

Oops!!!! this should be the 100th time this question

Check this link..

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

[Former Member]

hi

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.

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 '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.

**reward if helpful

regards,

madhu