第一句话赋给belt的no是初始值，一旦最后一句调用程序时赋予了belt新的值No，将会覆盖初始值。
ps：如果这时第一句用％let定义了全局变量，则以％let赋的值具有最高优先执行权，具体优先执行规则如下：
％let语句中赋的值〉调用程序时赋的值〉程序开始时赋的初始值

dingding

问一下这里的\是起什么作用的？

%HIGHWAY(Belt=No)    -----------------  调用的时候赋了值 No，所以答案是 3 条吧。

/    是转义字符 , 所以这个语句 相当于  where Seatbelt=\”&Belt\” ; 相当于 ------------>  where Seatbelt=*No* ;这个条件。

For example, if the variable X contains the values abc, a_b, and axb, the following LIKE operator with an escape character selects only the value a_b. The escape character (/) specifies that the pattern searches for a literal ' _' that is surrounded by the characters a and b. The escape character (/) is not part of the search.

where x like 'a/_b' escape '/';

Without an escape character, the following LIKE operator would select the values a_b and axb. The special character underscore in the search pattern matches any single b character, including the value with the underscore:


where x like 'a_b';

谢谢！！！