如何把oracle表中的全角字符转换为半角字符？

a表包含全角字符的字段：address

update a set a.address =(to_single_byte(a.address))

执行，提交，即可。函数解释：

转换成半角函数： to_single_byte(s)

转换成全角函数:   to_multi_byte(s)

但是，to_single_byte(s)和to_multi_byte(s)函数发挥作用的前提是数据库字符集包括单字节字符和多字节字符。

oracle数据库安装的是GBK字符集，但是查看表的内码，发现表的数据是用unicode字符集存储的，暂时还未搞明白是怎么回事。。。。。

如果数据库不包含这些字符，需要用repalce()函数，分别手工去替换：

update a t set t.address = replace(t.address,'Ａ','A')

update a t set t.address = replace(t.address,'Ｂ','B')

update a t set t.address = replace(t.address,'Ｃ','C')

update a t set t.address = replace(t.address,'Ｄ','D')

update a t set t.address = replace(t.address,'Ｅ','E')

update a t set t.address = replace(t.address,'Ｆ','F')

update a t set t.address = replace(t.address,'Ｇ','G')

update a t set t.address = replace(t.address,'Ｈ','H')

update a t set t.address = replace(t.address,'Ｉ','I')

update a t set t.address = replace(t.address,'Ｊ','J')

update a t set t.address = replace(t.address,'Ｋ','K')

update a t set t.address = replace(t.address,'Ｌ','L')

update a t set t.address = replace(t.address,'Ｍ','M')

update a t set t.address = replace(t.address,'Ｎ','N')

update a t set t.address = replace(t.address,'Ｏ','O')

update a t set t.address = replace(t.address,'Ｐ','P')

update a t set t.address = replace(t.address,'Ｑ','Q')

update a t set t.address = replace(t.address,'Ｒ','R')

update a t set t.address = replace(t.address,'Ｓ','S')

update a t set t.address = replace(t.address,'Ｔ','T')

update a t set t.address = replace(t.address,'Ｕ','U')

update a t set t.address = replace(t.address,'Ｖ','V')

update a t set t.address = replace(t.address,'Ｗ','W')

update a t set t.address = replace(t.address,'Ｘ','X')

update a t set t.address = replace(t.address,'Ｙ','Y')

update a t set t.address = replace(t.address,'Ｚ','Z')

update a t set t.address = replace(t.address,'－','-')

update a t set t.address = replace(t.address,'０','0')

update a t set t.address = replace(t.address,'１','1')

update a t set t.address = replace(t.address,'２','2')

update a t set t.address = replace(t.address,'３','3')

update a t set t.address = replace(t.address,'４','4')

update a t set t.address = replace(t.address,'５','5')

update a t set t.address = replace(t.address,'６','6')

update a t set t.address = replace(t.address,'７','7')

update a t set t.address = replace(t.address,'８','8')

update a t set t.address = replace(t.address,'９','9')

手工写入这些好麻烦，有没有自动化的一点的办法？