Some procedures may need non-zero divisor. You can add a if statement to bypass it like,

lf a ne 0 then b=z/a;
else              b='your definition' here according to you problem.

我找到解决办法了
Floating Point Zero Divide这个问题在proc psmatch里面的解决办法：
https://support.sas.com/kb/62/744.html
不知道楼主是在哪个proc中遇到的，你可以在下面这个网址找一下有没有你的解决办法：
https://support.sas.com/techsup/reports/maintSAS94/SAS94_TS1M6_issues_addressed.html
或者在SAS support里面查一下：
https://support.sas.com/en/search.html?q=Floating%20point%20zero%20divide%20error