自定义oracle字符串分割函数split

（1）定义split_type类型：

CREATE OR REPLACE TYPE split_type IS TABLE OF VARCHAR2 (4000)
/

（2）定义split函数：

CREATE OR REPLACE FUNCTION ETL.split (
    p_str       IN VARCHAR2, 
    p_delimiter IN VARCHAR2 default(',') --分隔符，默认逗号
)
    RETURN split_type
IS
    j INT := 0;
    i INT := 1;
    len INT := 0;
    len1 INT := 0;
    str VARCHAR2 (4000);
    my_split split_type := split_type ();
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);
             my_split.EXTEND;
             my_split (my_split.COUNT) := str;

            IF i >= len
            THEN
                EXIT;
            END IF;
        ELSE
            str := SUBSTR (p_str, i, j - i);
            i := j + len1;
            my_split.EXTEND;
            my_split (my_split.COUNT) := str;
        END IF;
    END LOOP;

    RETURN my_split;
END split;
/

（3）测试split函数：

select * from table (split('1,2,3,4',','))