函數語法:sign( n)
函數說明:判定值n的符號,若 n > 0,返回是 1;若 n < 0,返回 -1;若 n = 0,則返回0。
函數示例:
一、select sign(100) as "正數100" , sign(-100) as "負數-100" , sign(0) as "零0" from dual;
二、a=10,b=20;
select sign(a-b) from dual; 結果:-1
select sign(b-a) from dual; 結果: 1