There are some problems when using numeric type to query string type fields in MySQL

problem

When querying record table data , Dirty data with spaces appears ： There is a space in front of the data , Pictured

reason

When MySQL When the field type and the incoming condition data type are inconsistent , There will be invisible data type conversion ;
If string starts with the a number , And it's all numbers , Then it is converted to a number, and the result is the whole string ;
Part of it is numbers , Then it is converted to a number, and the result is up to the first character that is not a number . understand ： varchar str = “1111aaaa”, The conversion to a number is 1111.
If the string does not start with a number , Then the result is 0 . varchar str = “aabb33” ; The conversion to a number is 0 .