在oracle中,''=null,在sql server中,''空字符串但是不为空,与null是两个概念。如果有空格' '代替'' 如下:
select userid,nullif(userpwd,' ')from t_sysuser where userid='张三'
select userid,nullif(userpwd,' ')from t_sysuser where userid='张三'
调试欢乐多
但是在oracle中怎么写呢?
=======>oracle:
select userid,nvl(userpwd,'')from t_sysuser where userid='张三'