Mysql enum not searching record without quote value - mysql

Question

I have table field with enum enum('0','1','2','3','4','5','6').
In query when I try with IN (1) it is not working but when I use IN ("1") it is working.
If I use In (1,2) it is working.
So when there is one value in "IN" clause then it should work without quote

Answer 1

ENUM values are defined and stored as strings. They can be accessed via their string value or via their numeric index value (which starts at 1 and not 0).
Your enum values start at '0' which would have a numeric index value of 1. So, it would be possible to get some data back from your query using IN(1,2) but those numbers will be treated as the index and you will actually get data returned for records where the enum values are '2' and '3' (probably not what you think you are getting back).
IN(1) doesn't work because you have no data with an index value of 1 (emum value = '0')
IN('1') does work because you do have data with an enum value of '1'
Try this for a practical example
http://sqlfiddle.com/#!9/3993b/1
or read the section on Handling of Enumeration Literals in the mysql documentation

Answer 2

You can use values as string or integer, IN() function support both types.
The IN operator allows you to specify multiple values in a WHERE clause.
Usually IN() function is using for multiples values but it does support single value also. For me all queries are working
SELECT * FROM `your_table` WHERE `id` IN('4') // String Number
SELECT * FROM `your_table` WHERE `id` IN('4','2','1') // String Multiple Number
SELECT * FROM `your_table` WHERE `id` IN(1) // Single Integer
SELECT * FROM `your_table` WHERE `id` IN(1,2,4) // Multiple Integer

Answer 3

Avoid using number as 'enumeration values'
Doucumenation quotes-We strongly recommend that you do not use numbers as enumeration values, because it does not save on storage over the appropriate TINYINT or SMALLINT type, and it is easy to mix up the strings and the underlying number values (which might not be the same) if you quote the ENUM values incorrectly. If you do use a number as an enumeration value, always enclose it in quotation marks. If the quotation marks are omitted, the number is regarded as an index. See Handling of Enumeration Literals to see how even a quoted number could be mistakenly used as a numeric index value.'
Link- https://dev.mysql.com/doc/refman/5.7/en/enum.html#enum-limits

Answer 4

enum supports accessing values either by numeric index of values or values that are directly quoted.
As per MySQL documentation on ENUM:
... strongly recommend that you do not use numbers as enumeration values,
because it does not save on storage over the appropriate TINYINT or SMALLINT type,
and it is easy to mix up the strings and the underlying number values
(which might not be the same) if you quote the ENUM values incorrectly.
If you do use a number as an enumeration value, always enclose it in quotation marks.
If the quotation marks are omitted, the number is regarded as an index.
Examples:
mysql> drop table if exists so_q48786040;
mysql> CREATE TABLE so_q48786040(e ENUM('6', '5', '4', '3', '2', '1', '0'));
mysql> INSERT INTO so_q48786040 VALUES( 2 ), ( 4 ), ( 7 ), ( '6' );
Query OK, 4 rows affected (0.05 sec)
Records: 4 Duplicates: 0 Warnings: 0
Selecting all rows, returns values 5,3,0,6
mysql> SELECT * FROM so_q48786040;
+------+
| e |
+------+
| 5 |
| 3 |
| 0 |
| 6 |
+------+
4 rows in set (0.00 sec)
Selecting at specific indices. Results will be in the order of enum indices defined.
mysql> SELECT * FROM so_q48786040 WHERE e IN( 7, 4 );
+------+
| e |
+------+
| 3 | -- <--- at index 4
| 0 | -- <--- at index 7
+------+
2 rows in set (0.00 sec)
Selecting at specific quoted literals. Results will be in the order of enum indices defined.
mysql> SELECT * FROM so_q48786040 WHERE e IN( '6', '3', '0' );
+------+
| e |
+------+
| 3 |
| 0 |
| 6 |
+------+
3 rows in set (0.00 sec)
Selecting a non existing entry. Returns empty set as '4' was not inserted
mysql> SELECT * FROM so_q48786040 WHERE e IN( '4' );
Empty set (0.00 sec)
NOTE:
It is suggested to define empty literals at index 0.
The index of the NULL value is NULL.