1.  select lpad(to_number('0001')+1,4,'0') from dual;

2.  select case when to_number('0010')+1<9 then '000'||to_char(to_number('0010')+1)            when to_number('0010')+1<99 then '00'||to_char(to_number('0010')+1)            when to_number('0010')+1<999 then '0'||to_char(to_number('0010')+1)       else to_char(to_number('0010')+1) end          from dual

参考下这个方案https://bbs.fanruan.com/thread-94635-1-1.html

select lpad('0010'+1,4,0) as a from dual

lpad(字符串,4,0)表示用0将字符串补齐到4位

string((emp_id + 1),'000')

select SUBSTR(CONCAT('0000','0010'+1),-4,4) FROM DUAL 

前方拼接0000然后取最后4位就行了