在N未知的Postgres中需要列的初始N个字符

我不完全确定我是否理解这个问题,但是 regexp_replace()

with sample (employeeid) as (
  values
  ('1ACR'),
  ('2ACRDCR'),
  ('100DCRAC')
)
select employeeid,
       regexp_replace(employeeid, 'ACR|AC|DCR|DC.*$', '', 'gi') as clean_id
from sample

退货:

employeeid | clean_id
-----------+---------
1ACR       | 1       
2ACRDCR    | 2       
100DCRAC   | 100     

会的 许多的 cleaner将此信息存储在两列中。一个是empid,一个是那些“代码”