oracle SQL单行函数1-字符函数汇总

/*
字符函数汇总实例
*/

--UPPER 小写转大写
SELECT UPPER('adafsadfs') FROM dual;
ADAFSADFS

--LOWER 大写转小写
SELECT LOWER('dddDDD') FROM dual;
dddddd

--initcap 英文首字母转大写
SELECT INITCAP('hello ! hao are you!')  FROM dual;
Hello ! Hao Are You!

--concat 字符串连接
SELECT CONCAT('ha','he') FROM dual;
SELECT 'ha'||'he' FROM dual;
hahe

--length 字段长度
SELECT LENGTH('hahahh') FROM dual;
6

--replace 替换
SELECT replace('hahahah','a','A') FROM dual;
hAhAhAh

--instr 在第一个字符串中查找第二个字符出现的位置
SELECT INSTR('i am china','chi') FROM dual
6

--lpad 左侧填充
SELECT LPAD('haha','8','*') FROM dual;
****haha

--rpad 右侧填充
SELECT RPAD('haha','8','*') FROM dual;
haha****

--trim 去除前后空格
SELECT TRIM('    he l lo   ') FROM dual;
he l lo
SELECT REPLACE(' he l l o ',' ','') FROM dual;
hello

--substr 截取字符串
SELECT SUBSTR('wo shi zhong guo ren ','0','9') FROM dual;
wo shi zh