最近項目過程中碰到對于數據進行排序按照升序排序需求。這需求貌似很簡單，我沒多想直接order by columnName。忽略了漢字排序的問題導致bug的出現。

業務要求，按照excel中排序出來的結果。對于漢字excel默認是按照拼音排序的，那么問題來了，oracle對于漢字究竟是如何排序的？

經查閱資料發現，對于oracle對漢字排序的問題網上說法不一。有的說是根據二進制編碼排序的，有的缺說是根據拼音排序的。

自己試了試，肯定默認不是拼音排序。可能是二進制編碼吧。

說下具體怎么改，也是轉載網上的一些方法。

1、語句級別設置排序方式：
? ? ?//按照筆劃排序?
? ?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，此為系統的默認排序方式?
? ?select * from dept order by nlssort(name,'NLS_SORT=SCHINESE_PINYIN_M');?
2、Session級別的設置，修改ORACLE字段的默認排序方式：
??????????????按拼音：alter session set nls_sort = SCHINESE_PINYIN_M;
??????????????按筆畫：alter session set nls_sort = SCHINESE_STROKE_M;
??????????????按偏旁：alter session set nls_sort = NLS_SORT=SCHINESE_RADICAL_M；
3、修改系統參數（數據庫所在操作系統）：
???????????????set NLS_SORT=SCHINESE_RADICAL_M ;export NLS_SORT （sh）setenv NLS_SORT SCHINESE_RADICAL_M (csh)??HKLCSOFTWAREORACLEhome0NLS_SORT (win注冊表)；

我這里只是用來語句級別的就可以了。

回到系統默認排序的問題就是設置數據庫的NLS_SORT 這個參數

通過查看select * from nls_database_parameters; 數據庫參數

我的默認值為BINARY

Oracle 官方說明：

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.

英文水平有限，大概BINARY?這個意思是二進制編碼排序的設定。

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