MySQL 使用等于 (=) 和 LIKE 以及字母数字标准值更新查询

Question

Recently noticed that a working UPDATE query has no longer same results with where clause that contains alphanumeric values leading with number, appreciate any help.

UPDATE query:

UPDATE `user` SET last_name = 'newTest' where `identifier` = '123abc';

ISSUE : This query updates all records with identifier begins with 123...

Fixed temporary the issue by using LIKE (see below):

UPDATE `user` SET last_name = 'newTest' where `identifier` LIKE '123abc';

But afraid there is some other similar cases in my code that could causes unacceptable data loss for clients.

EDIT : query with the issue is when I update another identifier that has the exact number leading other identifiers:

UPDATE `user` SET last_name = 'newTest' where `identifier` = 123;

Tech. versions used: php 7, mysql 5.6, RedBean 5, OS Alpine 3.11

Answer 1

The problem is that you compare a string value and a numeric value:

where `identifier` = 123

so Mysql does an implicit conversion of the column identifier to numeric and since the values 123abc or 123... start with 123 , they are all converted to 123 and the condition returns TRUE for all the values that start with 123 .
You can see this behavior here .
What you want is string comparison.
So change to:

where `identifier` = '123...'

This way you do a string comparison.