what is the difference between select single * and slect upto 1 rows...

what is the difference between select single *
and slect upto 1 rows...

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what is the difference between select single * and slect upto 1 rows.....

Answer / anita

select up to one rows is much quicker that select single
as your not really using the all the key fields. Select
single is a construct that is designed primarily to read
database records with a primary key. If there is no primary
key available then at the most it might end up doing a
perfunctory sequential search. However in the case of
select up to one rows it will assume that there is no
primary key and will automatically search for the most
appropriate index.

In select * single only a single record is fetched that is
whichever one will come first in the data base query. But
in the case of select upto one rows all the records will be
fetched and stored in a buffer which pertain to the where
condition in the Data base theory.

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what is the difference between select single * and slect upto 1 rows.....

Answer / gohila.r

Select Single * will pickup only one matching record from
the database into the buffer, and returns the same to the
internal table.

Select upto 1 rows will pickup all the records matching the
condition into the buffer, but return the top record to the
internal table.

For this reason, performance wise select upto 1 row is
better than select upto 1 row.
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.

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what is the difference between select single * and slect upto 1 rows.....

Answer / bandivenkateswarlu

the select single is used retrive the single record from the
database. where as in the select single up to one row is
used retrive one row from the databse.

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