convert函数 （oracle和sqlserver）

1.在oracle中，一般是把一个字符串从一种编码类型转换成另一种编码类型

http://download.oracle.com/docs/cd/B14117_01/server.101/b10759/functions023.htm#sthref1160

CONVERT

Syntax
convert::=

CONVERT(char, dest_char_set[, source_char_set ])

Purpose

CONVERT converts a character string from one character set to another. The datatype of the returned value is VARCHAR2.

• The char argument is the value to be converted. It can be any of the datatypes CHAR, VARCHAR2, NCHAR, NVARCHAR2, CLOB, or NCLOB.

• The dest_char_set argument is the name of the character set to which char is converted.

• The source_char_set argument is the name of the character set in which char is stored in the database. The default value is the database character set.

Both the destination and source character set arguments can be either literals or columns containing the name of the character set.

For complete correspondence in character conversion, it is essential that the destination character set contains a representation of all the characters defined in the source character set. Where a character does not exist in the destination character set, a replacement character appears. Replacement characters can be defined as part of a character set definition.

Examples

The following example illustrates character set conversion by converting a Latin-1 string to ASCII. The result is the same as importing the same string from a WE8ISO8859P1 database to a US7ASCII database.

SELECT CONVERT('Ä Ê Í Ó Ø A B C D E ', 'US7ASCII', 'WE8ISO8859P1') 
   FROM DUAL; 

CONVERT('ÄÊÍÓØABCDE' 
--------------------- 
A E I ? ? A B C D E ? 

Common character sets include:

• US7ASCII: US 7-bit ASCII character set

• WE8DEC: West European 8-bit character set

• F7DEC: DEC French 7-bit character set

• WE8EBCDIC500: IBM West European EBCDIC Code Page 500

• WE8ISO8859P1: ISO 8859-1 West European 8-bit character set

• UTF8: Unicode 3.0 UTF-8 Universal character set, CESU-8 compliant

• AL32UTF8: Unicode 3.1 UTF-8 Universal character set

 

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2.SQLSERVER

http://gjbxx110.blog.51cto.com/794841/297007