|
henryyhl 发表于 2013-8-9 16:58 
刚才看了一下,是9.3新加的选择项。详见:http://support.sas.com/documentation/cdl/en/whatsnew/64209/HT ...
在网站http://support.sas.com/documenta ... 4n1b6l00ftdnxge.htm
看到这个:
NOUNIQUEKEY
checks for and eliminates observations from the output data set that have a unique sort key. A sort key is unique when the observation containing the key is the only observation within a BY group. An observation has a unique sort key when it is the only observation within a BY group.
Note: Unlike NODUPKEY, which writes one observation of a BY group to the output data set and discards all other observations from the BY group, the NOUNIQUEKEY maintains BY group integrity. Either all observations of a BY group are written to the output data set when the BY group consists of two or more observations, or all observations of the BY group are discarded when the BY group consists of a single observation.
Alias:NOUNIKEY | NOUNIKEYS | NOUNIQUEKEYS
大概就是说如果by变量的某个值只有一个观测的话就删除,如果该by变量的值有多个观测则保留这些观测。
这是9.3上新加的,本人用的还是9.2,没法测试啊。 |
|