我正在尝试使用REGEXP_REPLACE与众不同,并返回0行.

我已经在MySQLP v8.0中创建了一个测试表

   CREATE TABLE phone(
   id serial primary key,
   phone_number char(25));

   INSERT INTO phone (phone_number)
   VALUES ('(423) 330-9999');

   INSERT INTO phone (phone_number)
   VALUES ('(423)3309999');

   INSERT INTO phone (phone_number)
   VALUES ('423-330-1111)');

   INSERT INTO phone (phone_number)
   VALUES ('1-423-330-6666');

   INSERT INTO phone (phone_number)
   VALUES ('1A423*330*1111');

   INSERT INTO phone (phone_number)
   VALUES ('5553301111');

– 然后

select 
   REGEXP_REPLACE(phone_number, '[^0-9]', '',1, 0, 'm') as clean_phone
from phone

—工作正常->
clean_phone
4233309999
4233309999
4233301111
14233306666
14233301111
5553301111

—计数

select 
   count(REGEXP_REPLACE(phone_number, '[^0-9]', '',1, 0, 'm')) as 
   clean_phone
from phone

—工作正常->
clean_phone
6

-独特的clean_phone

select 
   distinct(REGEXP_REPLACE(phone_number, '[^0-9]', '',1, 0, 'm')) as 
   clean_phone
from phone

—返回空->
clean_phone

我不明白为什么区分不起作用？

解决方法:

Distinct不是函数,因此您不需要distinct(),而仅需要distinct

select  distinct REGEXP_REPLACE(phone_number, '[^0-9]', '',1, 0, 'm') as 
   clean_phone
from phone

.

    select distinct  clear_phone from(
    select   REGEXP_REPLACE(phone_number, '[^0-9]', '',1, 0, 'm')  clear_phone
   from phone ) t 

如果错误仍然存​​在,您可以尝试使用虚拟表的插入/选择

  insert into dummy_table(clear_phone)
  select   REGEXP_REPLACE(phone_number, '[^0-9]', '',1, 0, 'm')  
  from phone;

  select distinct clear_phone from dummy_table;