74 /*计算两个日期之间间隔多少天:开始时间01DEC2005 结束日期:31JUL2018*/
75 %LET N2='31JUL2018'D-'01DEC2005'D+1;
76 %PUT &N2.;
'31JUL2018'D-'01DEC2005'D+1
直接输出字符:'31JUL2018'D-'01DEC2005'D+1
86 %LET N2=%SYSEVALF('31JUL2018'D-'01DEC2005'D+1);
87 %PUT &N2.;
4626
正确输出:4626
注意:区别在于%SYSEVALF函数