mysql where exact match

Question

When i write this query

SELECT cd.title, cd.city FROM coupon_detail cd WHERE cd.id = 260;

return

title            city  
--         


        

Answer 1

This is happening because of Type Conversion in MySql. My sql treats '260abcxyz' as an integer in your query and AFAIK because first char is number MySql casts it to a number and it becomes only 260 and that's why you are getting result. If you write character first like 'abcxyz260' it will successes the comparison.

More explanation available here: Type Conversion in MySql

As a solution: you should take care that only numbers are passed in comparison and not combination of string and number.

Answer 2

use like instead = because if the string is too long than exact match won't work in that way
SELECT cd.title, cd.city FROM coupon_detail cd WHERE cd.id LIKE '260abcxyz';

Answer 3

You could convert the id to a string so the comparison will be done exactly. You could use LIKE to cause an implicit conversion

SELECT cd.title, cd.city FROM coupon_detail cd WHERE cd.id LIKE '260abcxyz';

or alternative, you can perform the cast explicitly

SELECT cd.title, cd.city FROM coupon_detail cd WHERE CAST(cd.id AS CHAR) = '260abcxyz';

However, if all your IDs are integers, it's probably more appropriate to check these values before you try to query the database. (If the ID you're querying with isn't a number, there can't be a match anyway.)

Answer 4

Well, you should not use quote if the id is INT. The way MySQL does is if you use String to compare a INT, it uses just the valid initial integer from start.

see this:

mysql> desc coupon_detail;
+-------+--------------+------+-----+---------+-------+
| Field | Type         | Null | Key | Default | Extra |
+-------+--------------+------+-----+---------+-------+
| id    | int(11)      | YES  |     | NULL    |       |
| title | varchar(100) | YES  |     | NULL    |       |
| city  | varchar(100) | YES  |     | NULL    |       |
+-------+--------------+------+-----+---------+-------+
3 rows in set (0.04 sec)

mysql> SELECT cd.title, cd.city FROM coupon_detail cd WHERE cd.id = 'ff260';
Empty set, 1 warning (0.00 sec)

mysql> SELECT cd.title, cd.city FROM coupon_detail cd WHERE cd.id = '260ff';
+-----------------+--------+
| title           | city   |
+-----------------+--------+
| Butterfly world | Mohali |
+-----------------+--------+
1 row in set, 1 warning (0.00 sec)

mysql> SELECT cd.title, cd.city FROM coupon_detail cd WHERE cd.id = 260;
+-----------------+--------+
| title           | city   |
+-----------------+--------+
| Butterfly world | Mohali |
+-----------------+--------+
1 row in set (0.00 sec)

mysql> SELECT cd.title, cd.city FROM coupon_detail cd WHERE cd.id = 26011;
Empty set (0.00 sec)

The idea is not to mix numbers and aphabets to compare a INT column. If you have to you may consider

• converting ID column to VARCHAR. In that case auto-increment may go away.
• have application logic to query only the strings that has numerics.