sql语句来增加字符串位数

用不用游标都可以，不用更简洁。
主要是用到一些字符串函数，如len--求字符串的长度，ltrim－－去除字符串的前导空格 rtrim---去除字符串的尾部空格

方法一：直接用update语句

update employee set empno='000'+ltrim(rtrim(empno)) where len(ltrim(rtrim(empno)))=3
update employee set empno='00'+ltrim(rtrim(empno)) where len(ltrim(rtrim(empno)))=4

方法二：采用游标
declare cur scroll cursor for select empno from employee for update
open cur
declare @ex char(10)
fetch first from cur into @ex
while @@fetch_status=0
begin
if len(ltrim(rtrim(@ex)))=3
update employee set empno='000'+ltrim(rtrim(empno)) where current of cur
else
if len(ltrim(rtrim(@ex)))=4
update employee set empno='00'+ltrim(rtrim(empno)) where current of cur
fetch next from cur into @ex
end
close cur
deallocate cur

必须用游标吗？
给个取巧的方法供你参考

update [employee] set [empno]=right(cast([empno] as varchar)