Mysql 查询返回错误结果

Question

I have a products table with a product_id field that is an auto-ID and an integer. When I search:

SELECT * FROM `products` WHERE product_id = '73N716507Y5928128'

it actually returns the row whose product_id is 73. And I may be new to programming but I KNOW that 73.= 73N716507Y5928128.

What can I do to fix this? The reason BTW for this query is that I am searching multiple tables and multiple fields for a search term and using logic to determine what the user is searching for...

Any help would be greatly appreciated.

Answer 1

In mysql, when you compare (=, <, >, <=, >=, <=>) a numeric field and a character field, the character field is converted to a number first, disregarding any trailing non-numeric characters.

Presumably you want the product_id= part to stay unchanged to take advantage of an index. You can add an additional condition to test if the input is in fact a number:

SELECT * FROM `products`
WHERE product_id = '73N716507Y5928128'
AND CONCAT(0+'73N716507Y5928128')='73N716507Y5928128';

Answer 2

Your business logic should ensure that only integers are passed in the where clause . However, you may also try the following, it will fix the issue. But if products table has millions of records, this will not be a good idea due to table full scan. But if there are say 10K or less products in the table, full scan will not be significant at all.

SELECT * FROM `products` WHERE binary(product_id) = '73N716507Y5928128'