oracle replace函数使用举例及语法简要
一. replace 函数用法如下:
replace('将要更改的字符串','被替换掉的字符串','替换字符串')
例:select replace ('111222333444','222','888') from dual;
输出为 '111888333444'
二. replace语法说明
语法:REPLACE ( char , search_string [, replacement_string] )
REPLACE returns char with every occurrence of search_string replaced with replacement_string. If replacement_string is omitted or null, then all occurrences of search_string are removed. If search_string is null, then char is returned.
解释:repalce中,每个search_string都被replacement_string所代替。
select replace('acdd','cd','ef') from dual;→ aefd
如果replacement_string为空或为NULL,那么所有的search_string都被移除。
select replace('acdd','cd','') from dual;→ad
如果search_string为null,那么就返回原来的char。
select replace('acdd','','ef') from dual;→acdd
select replace('acdd','','') from dual;→acdd(也是两者都为空的情况)