Substr usage, substr

Substr usage, substr

Sqlplus conn user/user -- connect to database

Show user -- display the current user

Select upper (substr ('liufeng',) as firstname, lower (substr ('liuyuehui', 4) as secondname from dual; -- display name

Substr ('string', 'start position ', 'length ');

If the start position is negative, the corresponding position is found from the right side of the string.

For example:

Select substr ('liueihui',-3, 3) -- the output result is hui.

The substr is offset from the right to the left by three characters, and then truncated by three characters. The output is hui.