SQL order string as number

问题

I have numbers saved as VARCHAR to a MySQL database. I can not make them INT due to some other depending circumstances.

It is taking them as character not as number while sorting.

In database I have

1 2 3 4 5 6 7 8 9 10...

On my page it shows ordered list like this:

1 10 2 3 4 5 6 7 8 9

How can I make it appear ordered by numbers ascending?

回答1:

If possible you should change the data type of the column to a number if you only store numbers anyway.

If you can't do that then cast your column value to an integer explicitly with

select col from yourtable
order by cast(col as unsigned)

or implicitly for instance with a mathematical operation which forces a conversion to number

select col from yourtable
order by col + 0

BTW MySQL converts strings from left to right. Examples:

string value  |  integer value after conversion
--------------+--------------------------------
'1'           |  1
'ABC'         |  0   /* the string does not contain a number, so the result is 0 */
'123miles'    |  123 
'$123'        |  0   /* the left side of the string does not start with a number */

回答2:

Another way, without using a single cast.

(For people who use JPA 2.0, where no casting is allowed)

select col from yourtable
order by length(col),col

EDIT: only works for positive integers

回答3:

The column I'm sorting with has any combination of alpha and numeric, so I used the suggestions in this post as a starting point and came up with this.

DECLARE @tmp TABLE (ID VARCHAR(50));
INSERT INTO @tmp VALUES ('XYZ300');
INSERT INTO @tmp VALUES ('XYZ1002');
INSERT INTO @tmp VALUES ('106');
INSERT INTO @tmp VALUES ('206');
INSERT INTO @tmp VALUES ('1002');
INSERT INTO @tmp VALUES ('J206');
INSERT INTO @tmp VALUES ('J1002');

SELECT ID, (CASE WHEN ISNUMERIC(ID) = 1 THEN 0 ELSE 1 END) IsNum
FROM @tmp
ORDER BY IsNum, LEN(ID), ID;

Results

ID
------------------------
106
206
1002
J206
J1002
XYZ300
XYZ1002

Hope this helps

回答4:

Another and simple way

ORDER BY ABS(column_name)

回答5:

Another way to convert.

If you have string field, you can transform it or its numerical part the following way: add leading zeros to make all integer strings having equal length.

ORDER BY CONCAT( REPEAT(  "0", 18 - LENGTH( stringfield ) ) , stringfield )

or order by part of a field something like 'tensymbols13', 'tensymbols1222' etc.

ORDER BY CONCAT( REPEAT(  "0", 18 - LENGTH( LEFT( stringfield , 10 ) ) ) , LEFT( stringfield , 10 ) )

回答6:

This works for me.

select * from tablename
order by cast(columnname as int) asc

回答7:

I was looking also a sorting fields that has letter prefix. Here is what i found out the solution. This might help who is looking for the same solution.

Field Values:

FL01,FL02,FL03,FL04,FL05,...FL100,...FL123456789

select SUBSTRING(field,3,9) as field from table order by SUBSTRING(field,3,10)*1 desc

SUBSTRING(field,3,9) i put 9 because 9 is way enough for me to hold max 9 digits integer values.

So the result will be 123456789 123456788 123456787 ... 100 99 ... 2 1

回答8:

This will handle negative numbers, fractions, string, everything:

ORDER BY ISNUMERIC(col) DESC, Try_Parse(col AS decimal(10,2)), col;

回答9:

Alter your field to be INT instead of VARCHAR.

I can not make them INT due to some other depending circumstances.

Then fix the depending circumstances first. Otherwise you are working around the real underlying issue. Using a MySQL CAST is an option, but it's masking your bad schema which should be fixed.

来源：https://stackoverflow.com/questions/11808573/sql-order-string-as-number

标签

mysql

sql

string

numbers

sql-order-by