如果一个字符串中有像逗号或其它符号分隔,你想把它折分成列,如’first field, second field , third field’,
拆成
first field
second field
third field
1.针对 '1','2','3','4','5'(逗号在字符串外面):
SQL> SELECT COLUMN_VALUE FROM TABLE(SYS.ODCIVARCHAR2LIST('1','2','3','4','5'));
COLUMN_VALUE
--------------------------------------------------------------------------------
1
2
3
4
5
2.针对'1,2,3,4,5'(逗号在字符串里面)(用10G开始支持的正则表达式):
SQL> select regexp_substr('1,2,3,4,5','[^,]+',1,rownum) from dual
2 connect by rownum<=length('1,2,3,4,5')-length(replace('1,2,3,4,5',','))+1
3 ;
REGEXP_SUBSTR('1,2,3,4,5','[^,
------------------------------
1
2
3
4
5
TIP:
REGEXP_SUBSTR 函数是把那个串以正则不是以,(逗号)开头的截取,第二个参数是取第几组,rownum伪列序号,connect 循环 ,循环次数为串总长度-去除分隔符后=几个分隔符 +1
3.使用函数
CREATE OR REPLACE TYPE ty_str_split IS TABLE OF VARCHAR2 (4000);
----------------------------------------------------------------
CREATE OR REPLACE FUNCTION fn_split (p_str IN CLOB, p_delimiter IN VARCHAR2)
RETURN ty_str_split
IS
j INT := 0;
i INT := 1;
len INT := 0;
len1 INT := 0;
str VARCHAR2 (4000);
str_split ty_str_split := ty_str_split ();
BEGIN
len := LENGTH (p_str);
len1 := LENGTH (p_delimiter);
WHILE j < len
LOOP
j := INSTR (p_str, p_delimiter, i);
IF j = 0
THEN
j := len;
str := SUBSTR (p_str, i);
str_split.EXTEND;
str_split (str_split.COUNT) := str;
IF i >= len
THEN
EXIT;
END IF;
ELSE
str := SUBSTR (p_str, i, j - i);
i := j + len1;
str_split.EXTEND;
str_split (str_split.COUNT) := str;
END IF;
END LOOP;
RETURN str_split;
END fn_split;
测试:
SQL> select * from table(fn_split('1,2,3,4,5',',')); --第二个单引号中是前面字符串中需要被分隔的字符
COLUMN_VALUE ----------------------------------- 1 2 3 4 5
SQL> select * from table(fn_split('1,2,3,4。5','。'));
COLUMN_VALUE ------------------------------------ 1,2,3,4 5
转自https://blog.csdn.net/wanglilin/article/details/7231712