最近项目过程中碰到对于数据进行排序按照升序排序需求。这需求貌似很简单，我没多想直接order by columnName。忽略了汉字排序的问题导致bug的出现。

业务要求，按照excel中排序出来的结果。对于汉字excel默认是按照拼音排序的，那么问题来了，oracle对于汉字究竟是如何排序的？

经查阅资料发现，对于oracle对汉字排序的问题网上说法不一。有的说是根据二进制编码排序的，有的却说是根据拼音排序的。

自己试了试，肯定默认不是拼音排序。可能是二进制编码吧。

说下具体怎么改，也是转载网上的一些方法。

1、语句级别设置排序方式：

//按照笔划排序

select * from dept order by nlssort(name,'NLS_SORT=SCHINESE_STROKE_M');

//按照部首排序

select * from dept order by nlssort(name,'NLS_SORT=SCHINESE_RADICAL_M');

//按照拼音排序，此为系统的默认排序方式

select * from dept order by nlssort(name,'NLS_SORT=SCHINESE_PINYIN_M');

2、Session级别的设置，修改ORACLE字段的默认排序方式：

按拼音：alter session set nls_sort = SCHINESE_PINYIN_M;

按笔画：alter session set nls_sort = SCHINESE_STROKE_M;

按偏旁：alter session set nls_sort = NLS_SORT=SCHINESE_RADICAL_M；

3、修改系统参数(数据库所在操作系统)：

set NLS_SORT=SCHINESE_RADICAL_M ;export NLS_SORT (sh)setenv NLS_SORT SCHINESE_RADICAL_M (csh)  HKLCSOFTWAREORACLEhome0NLS_SORT (win注册表)；

我这里只是用来语句级别的就可以了。

回到系统默认排序的问题就是设置数据库的NLS_SORT 这个参数

通过查看select * from nls_database_parameters; 数据库参数

我的默认值为BINARY

Oracle 官方说明：

Property

Description

Parameter type

String

Syntax

NLS_SORT = { BINARY | linguistic_definition }

Default value

Derived from NLS_LANGUAGE

Modifiable

ALTER SESSION

Range of values

BINARY or any valid linguistic definition name

If the value is BINARY, then the collating sequence for ORDER BY queries is based on the numeric value of characters (a binary sort that requires less system overhead).

If the value is a named linguistic sort, sorting is based on the order of the defined linguistic sort. Most (but not all) languages supported by the NLS_LANGUAGE parameter also support a linguistic sort with the same name.

Note:

Setting NLS_SORT to anything other than BINARY causes a sort to use a full table scan, regardless of the path chosen by the optimizer. BINARY is the exception because indexes are built according to a binary order of keys. Thus the optimizer can use an index to satisfy the ORDER BY clause when NLS_SORT is set to BINARY. If NLS_SORT is set to any linguistic sort, the optimizer must include a full table scan and a full sort in the execution plan.

You must use the NLS_SORT operator with comparison operations if you want the linguistic sort behavior.

BINARY是二进制编码排序的设定。