Sorting '£' (pound symbol) in sql - sql

Question

I am trying to sort £ along with other special characters, but its not sorting properly.
I want that string to be sorted along with other strings starting with special characters. For example I have four strings:
&!##
££$$
abcd
&#$%.
Now its sorting in the order: &!##, &#$%, abcd, ££$$.
I want it in the order: &!##, &#$%, ££$$, abcd.
I have used the function order by replace(column,'£','*') so that it sorts along with strings starting with *. Although this seems to work while querying the DB, when used in code and deployed the £ gets replaced by �, i.e. (replace(column,'�','*') in the query, and doesn't sort as expected.
How to resolve this issue? Is there any other solution to sort the pound symbol/£? Any help would be greatly appreciated.

Answer 1

You seem to have two problems; performing the actual sort, and (possibly) how the £ symbol appears in the results in your code. Without knowing anything about your code or client or environment it's rather hard to guess what you might need to change, but I'd start by looking at your NLS_LANG and other NLS settings at the client end. #amccausl's link might be useful, but it depends what you're doing. I suspect you'll find different values in nls_session_parameters when queried from SQL*Plus and from your code, which may give you some pointers.
The sorting itself is slightly clearer now. Have a look at the docs for Linguistic Sorting and String Searching and NLSSORT.
You can do something like this (with a CTE to generate your data):
with tmp_tab as (
select '&!##' as value from dual
union all select '££$$' from dual
union all select 'abcd' from dual
union all select '&#$%' from dual
)
select * from tmp_tab
order by nlssort(value, 'NLS_SORT = WEST_EUROPEAN')
VALUE
------
&!##
&#$%
££$$
abcd
4 rows selected.
You can get sort values supported by your configuration with select value from v$nls_valid_values where parameter = 'SORT', but WESTERN_EUROPEAN seems to do what you want, for this sample data anyway.
You can see the default sorting in your current session with select value from nls_session_parameters where parameter = 'NLS_SORT'. (You can change that with an ALTER SESSION, but it's only letting me do that with some values, so that may not be helpful here).

Answer 2

You need to make sure your application code is all proper UTF-8 (see http://htmlpurifier.org/docs/enduser-utf8.html for more details)

Answer 3

Seems like your issue is with db characterset, or difference in charactersets between the app and db. For Oracle side, you can check by doing:
select value from sys.nls_database_parameters where parameter='NLS_CHARACTERSET';
If this comes up ascii (like US7ASCII), then you may have issues storing the data properly. Even if this is the charset, you should be able to insert and retrieve sorted (binary sort) by using nvarchar2 and unistr (assuming they conform to your NLS_NCHAR_CHARACTERSET, see above query but change parameter), like:
create table test1(val nvarchar2(100));
insert into test1(val) values (unistr('\00a3')); -- pound currency
insert into test1(val) values (unistr('\00a5')); -- yen currency
insert into test1(val) values ('$'); -- dollar currency
commit;
select * from test1
order by val asc;
-- will give symbols in order: dollar('\0024'), pound ('\00a3'), yen ('\00a5')
I will say that I would not resort to using the national characterset, I would probably change the db characterset to fit the needs of my data, as supporting 2 diff character sets isn't ideal, but its available anyway
If you have no issues storing/retrieving on the data side, then your app/client characterset is probably different than your db.

Answer 4

Use nchar(168). It will work.
select nchar(168)