在SAS数据步骤中使用WHERE SAME AND运算符

Question

我是SAS语言学习的初学者。我了解到SAS中有五个Special_where操作员。其中一个是WHERE SAME AND运算符。有人能帮我如何使用的例子吗

提前感谢

Answer 1

您可以在DATA步骤中使用WHERE语句，也可能在PROC步骤中更有用。WHERE SAME AND在它的另一个名称WHERE ALSO下可能更容易记住，它将允许您使用多个语句来添加更多的限制。

这一点很容易通过以下示例看到：

proc means data=sashelp.class ;
where sex='M';
where also age > 12 ;
var height;
run;

因为SAS将把得到的子设置条件回显到LOG。

1334  proc means data=sashelp.class ;
1335    where sex='M';
1336    where also age > 12 ;
NOTE: WHERE clause has been augmented.
1337    var height;
1338  run;
NOTE: Multiple concurrent threads will be used to summarize data.
NOTE: There were 6 observations read from the data set SASHELP.CLASS.
WHERE (sex='M') and (age>12);

请注意，如果同时使用WHERE和WHERE ALSO语句，则顺序会有所不同。

1339  proc means data=sashelp.class ;
1340    where also age > 12 ;
NOTE: WHERE clause has been augmented.
1341    where sex='M';
NOTE: WHERE clause has been replaced.
1342    var height;
1343  run;
NOTE: Multiple concurrent threads will be used to summarize data.
NOTE: There were 10 observations read from the data set SASHELP.CLASS.
WHERE sex='M';

但您总是可以对所有语句使用WHERE ALSO，然后顺序就无关紧要了。

1344  proc means data=sashelp.class ;
1345    where also age > 12 ;
NOTE: WHERE clause has been augmented.
1346    where also sex='M';
NOTE: WHERE clause has been augmented.
1347    var height;
1348  run;
NOTE: Multiple concurrent threads will be used to summarize data.
NOTE: There were 6 observations read from the data set SASHELP.CLASS.
WHERE (age>12) and (sex='M');