Oralce字符串函数！

常用的字符串函数：

SQL> select instr('Hello World!','o',1,1),instr('Hello World!','o',1,2),instr('Hello World!','o',6,2) from dual;

INSTR('HELLOWORLD!','O',1,1) INSTR('HELLOWORLD!','O',1,2) INSTR('HELLOWORLD!','O',6,2)

---------------------------- ---------------------------- ----------------------------

5 8 0

SQL> select substr('Hello World!',1,4),substr('Hello World!',3,4) from dual;

SUBSTR('HELLOWORLD!',1,4) SUBSTR('HELLOWORLD!',3,4)

------------------------- -------------------------

Hell llo

SQL> SELECT TRANSLATE('as f as f as bbdd', ' afb', '*?@') FROM DUAL;

TRANSLATE('ASFASFASBBDD','AFB'

------------------------------PS:每个字符匹配替换

?s*@*?s*@*?s*dd

SQL> SELECT REPLACE('as f af af as', 'af', 't') FROM DUAL;

REPLACE('ASFAFAFAS','AF','T')

-----------------------------PS:字符串匹配替换

as f t t as

SQL> select lpad('aaa',10,'#') from dual;

LPAD('AAA',10,'#')(默认为空格)

------------------

#######aaa

SQL> select rpad('aaa',10,'#') from dual;

RPAD('AAA',10,'#')(默认为空格)

------------------

aaa#######

ltrim(字符串1,字符串2) 和rtrim(字符串1,字符串2)

PS:从字符串1的左端开始扫描,逐一去掉在字符串2中出现的字符,当遇到不是字符串2中的字符终止,返回结果集.

SQL> select ltrim('morning','m'),ltrim('morning','or') from dual;

LTRIM('MORNING','M') LTRIM('MORNING','OR')

-------------------- ---------------------

orning morning

SQL> select rtrim('morning','m'),rtrim('morning','ng') from dual;

RTRIM('MORNING','M') RTRIM('MORNING','NG')

-------------------- ---------------------

morning morni

SQL> select trim('a' from 'abcaa') from dual;

TRIM('A'FROM'ABCAA')

--------------------PS:截取的字符集(蓝色部分)只能为一个字符

bc

SQL> select initcap('huang-kai-bin') from dual;

INITCAP('HUANG-KAI-BIN')

------------------------

Huang-Kai-Bin

SQL> select length('hello world') from dual;

LENGTH('HELLOWORLD')

--------------------

11

SQL> select upper('Hello World') from dual;

UPPER('HELLOWORLD')

-------------------

HELLO WORLD

SQL> select lower('Hello World') from dual;

LOWER('HELLOWORLD')

-------------------

hello world

SQL> select concat('Hello',' World') from dual;

CONCAT('HELLO','WORLD')

-----------------------ps:效果和字符串连接符 || 相同

Hello World

写了一个简单的过程，把一个分段记录插入表中：

在这个过程中，用到了两个字符串的函数：

1.SUBSTR(目标字符串，输出的子串的起点，子串的长度)

如：select substr(ssn,1,3)|| ','||substr(ssn,4,2)||','||substr(ssn,6,4);

输出: ssn ssn

300541117 变成 300-54-1117

2.INSTR(目标字符串，匹配的内容，搜索起点，第几个满足条件)

如：select lastname,instr(lastname,'o',2,1) from characters;

输出: lastname instr(lastname,'o',2,1)

purvis 0

kong 2

create or replace procedure p_hyj_hkb_test is

v_in_string varchar2(10000);

v_post number(4);

v_out_string varchar2(5000);

v_cn number(1);

create_table varchar2(500);

v_name varchar2(20);

v_age number(2);

v_address varchar2(100);

i number(2);

v_in_string2 varchar2(10000);

--v_post2 number(4);

begin

begin

select count(*)

into v_cn

from user_tables a

where a.table_name = 'USER_INFO';

if v_cn = 0 then

--表不存在,建立

create_table := 'create table user_info(name varchar2(15),

age number(6),

address varchar2(100))';

execute immediate create_table;

else

--表存在

null;

end if;

end;

begin

--把串'黄开彬,25,福建省福州市闽清,'写到一个表里，字段要按user_name,age,address这三个字段来保存

v_in_string := '黄开彬,25,福建省福州市闽清县;黄依江,30,福建省福州市;小黄,35,福建省垃圾的;';

while instr(v_in_string, ';', 1) > 0 loop

if v_in_string is null then

goto end_loop;

end if;

v_post := instr(v_in_string, ';', 1);

v_in_string2 := substr(v_in_string, 1, v_post - 1)||',';

v_in_string := substr(v_in_string, v_post + 1);

i := 1;

while instr(v_in_string2, ',', 1) > 0 loop

if v_in_string2 is null then

goto end_loop;

end if;

v_post := instr(v_in_string2, ',', 1);

v_out_string := substr(v_in_string2, 1, v_post - 1);

v_in_string2 := substr(v_in_string2, v_post + 1);

if i = 1 then

v_name := v_out_string;

elsif i = 2 then

v_age := v_out_string;

elsif i = 3 then

v_address := v_out_string;

end if;

i := i + 1;

end loop;

--插入表

begin

-- insert into user_info values (v_name, v_age, v_address);

create_table := 'insert into user_info values(' || '''' || v_name || '''' || ',' || '''' ||

v_age || '''' || ',' || '''' || v_address || '''' || ')';

execute immediate create_table;

end;

end loop;

end;

<<end_loop>>

null;

end p_hyj_hkb_test;