how to check for 10 digits

Question

I have a phone number field. To be a valid phone number there has to be only 10 digits. How can I look in my phone number field which numbers are not 10 digits and then delete them? thanks

Answer 1

I believe you should validate it first before inserting the phone number into the database.

Although i believe that it is possible if you use

Delete from Table where (Select statement here);

But it's not going to reflect well in your overall program, in terms of performance and reusability

Answer 2

假设您在该字段中没有任何“-”，

mysql> DELETE FROM Table WHERE PHONE_NUM NOT RLIKE '[0-9]{10}'