标签：select single select up to one row
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.
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.
what is the difference of select single and select up to one row in abap
标签：select single select up to one row
原文地址：http://blog.csdn.net/champaignwolf/article/details/45332971
