將逗號分隔的字符串轉換爲PL/SQL中的數組

Question

如何將逗號分隔的字符串轉換爲數組？

我輸入'1,2,3'，我需要將其轉換爲數組。

Answer 1

Oracle提供了一個內置函數：dbms_utility.comma_to_table（http://download.oracle.com/docs/cd/E11882_01/appdev.112/e16760/d_util.htm#ARPLS73224）。

不幸的是，這一個不帶數字工作：

SQL> declare 
    2 l_input varchar2(4000) := '1,2,3'; 
    3 l_count binary_integer; 
    4 l_array dbms_utility.lname_array; 
    5 begin 
    6 dbms_utility.comma_to_table 
    7 (list => l_input 
    8 , tablen => l_count 
    9 , tab => l_array 
10 ); 
11 dbms_output.put_line(l_count); 
12 for i in 1 .. l_count 
13 loop 
14  dbms_output.put_line 
15  ('Element ' || to_char(i) || 
16  ' of array contains: ' || 
17  l_array(i) 
18  ); 
19 end loop; 
20 end; 
21/
declare 
* 
ERROR at line 1: 
ORA-00931: missing identifier 
ORA-06512: at "SYS.DBMS_UTILITY", line 132 
ORA-06512: at "SYS.DBMS_UTILITY", line 164 
ORA-06512: at "SYS.DBMS_UTILITY", line 218 
ORA-06512: at line 6 

但有一點招用 'X'，它的工作原理前綴的元素：

SQL> declare 
    2 l_input varchar2(4000) := '1,2,3'; 
    3 l_count binary_integer; 
    4 l_array dbms_utility.lname_array; 
    5 begin 
    6 dbms_utility.comma_to_table 
    7 (list => regexp_replace(l_input,'(^|,)','\1x') 
    8 , tablen => l_count 
    9 , tab => l_array 
10 ); 
11 dbms_output.put_line(l_count); 
12 for i in 1 .. l_count 
13 loop 
14  dbms_output.put_line 
15  ('Element ' || to_char(i) || 
16  ' of array contains: ' || 
17  substr(l_array(i),2) 
18  ); 
19 end loop; 
20 end; 
21/
3 
Element 1 of array contains: 1 
Element 2 of array contains: 2 
Element 3 of array contains: 3 

PL/SQL procedure successfully completed. 

問候， 搶。

Answer 2

我BBDD快速搜索帶我到一個函數稱爲分：

create or replace function split 
( 
p_list varchar2, 
p_del varchar2 := ',' 
) 
return split_tbl pipelined 
is 
l_idx pls_integer; 
l_list varchar2(32767) := p_list;AA 
l_value varchar2(32767); 
begin 
loop 
l_idx := instr(l_list,p_del); 
if l_idx > 0 then 
pipe row(substr(l_list,1,l_idx-1)); 
l_list := substr(l_list,l_idx+length(p_del)); 
else 
pipe row(l_list); 
exit; 
end if; 
end loop; 
return; 
end split; 

我不知道這是否會使用，但我們發現它here ...

Answer 3

是的，dbms_utility.comma_to_table僅支持逗號分隔列表，並且僅當列表中的元素是有效的PL/SQL標識（因此數字會導致錯誤）時，這是非常令人沮喪的。

我已經創建了一個通用的解析包，可以做你需要的東西（粘貼在下面）。它是我的「demo.zip」文件的一部分，該文件是支持我的培訓材料的超過2000個文件的存儲庫，所有這些文件均可在PL/SQL Obsession上獲得：www.toadworld.com/SF。

問候， 史蒂芬斯坦 www.plsqlchallenge.com （每日PL/SQL測驗）

CREATE OR REPLACE PACKAGE parse 
/* 
    Generalized delimited string parsing package 

    Author: Steven Feuerstein, steven@stevenfeuerstein.com 

    Latest version always available on PL/SQL Obsession: 

    www.ToadWorld.com/SF 

    Click on "Trainings, Seminars and Presentations" and 
    then download the demo.zip file. 

    Modification History 
     Date   Change 
     10-APR-2009 Add support for nested list variations 

    Notes: 
    * This package does not validate correct use of delimiters. 
     It assumes valid construction of lists. 
    * Import the Q##PARSE.qut file into an installation of 
     Quest Code Tester 1.8.3 or higher in order to run 
     the regression test for this package. 

*/ 
IS 
    SUBTYPE maxvarchar2_t IS VARCHAR2 (32767); 

    /* 
    Each of the collection types below correspond to (are returned by) 
    one of the parse functions. 

    items_tt - a simple list of strings 
    nested_items_tt - a list of lists of strings 
    named_nested_items_tt - a list of named lists of strings 

    This last type also demonstrates the power and elegance of string-indexed 
    collections. The name of the list of elements is the index value for 
    the "outer" collection. 
    */ 
    TYPE items_tt IS TABLE OF maxvarchar2_t 
         INDEX BY PLS_INTEGER; 

    TYPE nested_items_tt IS TABLE OF items_tt 
           INDEX BY PLS_INTEGER; 

    TYPE named_nested_items_tt IS TABLE OF items_tt 
            INDEX BY maxvarchar2_t; 

    /* 
    Parse lists with a single delimiter. 
    Example: a,b,c,d 

    Here is an example of using this function: 

    DECLARE 
     l_list parse.items_tt; 
    BEGIN 
     l_list := parse.string_to_list ('a,b,c,d', ','); 
    END; 
    */ 
    FUNCTION string_to_list (string_in IN VARCHAR2, delim_in IN VARCHAR2) 
     RETURN items_tt; 

    /* 
    Parse lists with nested delimiters. 
    Example: a,b,c,d|1,2,3|x,y,z 

    Here is an example of using this function: 

    DECLARE 
     l_list parse.nested_items_tt; 
    BEGIN 
     l_list := parse.string_to_list ('a,b,c,d|1,2,3,4', '|', ','); 
    END; 
    */ 
    FUNCTION string_to_list (string_in  IN VARCHAR2 
          , outer_delim_in IN VARCHAR2 
          , inner_delim_in IN VARCHAR2 
          ) 
     RETURN nested_items_tt; 

    /* 
    Parse named lists with nested delimiters. 
    Example: letters:a,b,c,d|numbers:1,2,3|names:steven,george 

    Here is an example of using this function: 

    DECLARE 
     l_list parse.named_nested_items_tt; 
    BEGIN 
    l_list := parse.string_to_list ('letters:a,b,c,d|numbers:1,2,3,4', '|', ':', ','); 
    END; 
    */ 
    FUNCTION string_to_list (string_in  IN VARCHAR2 
          , outer_delim_in IN VARCHAR2 
          , name_delim_in IN VARCHAR2 
          , inner_delim_in IN VARCHAR2 
          ) 
     RETURN named_nested_items_tt; 

    PROCEDURE display_list (string_in IN VARCHAR2 
         , delim_in IN VARCHAR2:= ',' 
         ); 

    PROCEDURE display_list (string_in  IN VARCHAR2 
         , outer_delim_in IN VARCHAR2 
         , inner_delim_in IN VARCHAR2 
         ); 

    PROCEDURE display_list (string_in  IN VARCHAR2 
         , outer_delim_in IN VARCHAR2 
         , name_delim_in IN VARCHAR2 
         , inner_delim_in IN VARCHAR2 
         ); 

    PROCEDURE show_variations; 

    /* Helper function for automated testing */ 
    FUNCTION nested_eq (list1_in IN items_tt 
        , list2_in IN items_tt 
        , nulls_eq_in IN BOOLEAN 
        ) 
     RETURN BOOLEAN; 

END parse; 
/

CREATE OR REPLACE PACKAGE BODY parse 
IS 
    FUNCTION string_to_list (string_in IN VARCHAR2, delim_in IN VARCHAR2) 
     RETURN items_tt 
    IS 
     c_end_of_list CONSTANT PLS_INTEGER := -99; 
     l_item   maxvarchar2_t; 
     l_startloc  PLS_INTEGER := 1; 
     items_out  items_tt; 

     PROCEDURE add_item (item_in IN VARCHAR2) 
     IS 
     BEGIN 
     IF item_in = delim_in 
     THEN 
      /* We don't put delimiters into the collection. */ 
      NULL; 
     ELSE 
      items_out (items_out.COUNT + 1) := item_in; 
     END IF; 
     END; 

     PROCEDURE get_next_item (string_in   IN  VARCHAR2 
          , start_location_io IN OUT PLS_INTEGER 
          , item_out    OUT VARCHAR2 
          ) 
     IS 
     l_loc PLS_INTEGER; 
     BEGIN 
     l_loc := INSTR (string_in, delim_in, start_location_io); 

     IF l_loc = start_location_io 
     THEN 
      /* A null item (two consecutive delimiters) */ 
      item_out := NULL; 
     ELSIF l_loc = 0 
     THEN 
      /* We are at the last item in the list. */ 
      item_out := SUBSTR (string_in, start_location_io); 
     ELSE 
      /* Extract the element between the two positions. */ 
      item_out := 
       SUBSTR (string_in 
        , start_location_io 
        , l_loc - start_location_io 
        ); 
     END IF; 

     IF l_loc = 0 
     THEN 
      /* If the delimiter was not found, send back indication 
       that we are at the end of the list. */ 

      start_location_io := c_end_of_list; 
     ELSE 
      /* Move the starting point for the INSTR search forward. */ 
      start_location_io := l_loc + 1; 
     END IF; 
     END get_next_item; 
    BEGIN 
     IF string_in IS NULL OR delim_in IS NULL 
     THEN 
     /* Nothing to do except pass back the empty collection. */ 
     NULL; 
     ELSE 
     LOOP 
      get_next_item (string_in, l_startloc, l_item); 
      add_item (l_item); 
      EXIT WHEN l_startloc = c_end_of_list; 
     END LOOP; 
     END IF; 

     RETURN items_out; 
    END string_to_list; 

    FUNCTION string_to_list (string_in  IN VARCHAR2 
          , outer_delim_in IN VARCHAR2 
          , inner_delim_in IN VARCHAR2 
          ) 
     RETURN nested_items_tt 
    IS 
     l_elements items_tt; 
     l_return  nested_items_tt; 
    BEGIN 
     /* Separate out the different lists. */ 
     l_elements := string_to_list (string_in, outer_delim_in); 

     /* For each list, parse out the separate items 
     and add them to the end of the list of items 
     for that list. */ 
     FOR indx IN 1 .. l_elements.COUNT 
     LOOP 
     l_return (l_return.COUNT + 1) := 
      string_to_list (l_elements (indx), inner_delim_in); 
     END LOOP; 

     RETURN l_return; 
    END string_to_list; 

    FUNCTION string_to_list (string_in  IN VARCHAR2 
          , outer_delim_in IN VARCHAR2 
          , name_delim_in IN VARCHAR2 
          , inner_delim_in IN VARCHAR2 
          ) 
     RETURN named_nested_items_tt 
    IS 
     c_name_position constant pls_integer := 1; 
     c_items_position constant pls_integer := 2; 
     l_elements   items_tt; 
     l_name_and_values items_tt; 
     l_return   named_nested_items_tt; 
    BEGIN 
     /* Separate out the different lists. */ 
     l_elements := string_to_list (string_in, outer_delim_in); 

     FOR indx IN 1 .. l_elements.COUNT 
     LOOP 
     /* Extract the name and the list of items that go with 
      the name. This collection always has just two elements: 
       index 1 - the name 
       index 2 - the list of values 
     */ 
     l_name_and_values := 
      string_to_list (l_elements (indx), name_delim_in); 
     /* 
     Use the name as the index value for this list. 
     */ 
     l_return (l_name_and_values (c_name_position)) := 
      string_to_list (l_name_and_values (c_items_position), inner_delim_in); 
     END LOOP; 

     RETURN l_return; 
    END string_to_list; 

    PROCEDURE display_list (string_in IN VARCHAR2 
         , delim_in IN VARCHAR2:= ',' 
         ) 
    IS 
     l_items items_tt; 
    BEGIN 
     DBMS_OUTPUT.put_line (
     'Parse "' || string_in || '" using "' || delim_in || '"' 
    ); 

     l_items := string_to_list (string_in, delim_in); 

     FOR indx IN 1 .. l_items.COUNT 
     LOOP 
     DBMS_OUTPUT.put_line ('> ' || indx || ' = ' || l_items (indx)); 
     END LOOP; 
    END display_list; 

    PROCEDURE display_list (string_in  IN VARCHAR2 
         , outer_delim_in IN VARCHAR2 
         , inner_delim_in IN VARCHAR2 
         ) 
    IS 
     l_items nested_items_tt; 
    BEGIN 
     DBMS_OUTPUT.put_line( 'Parse "' 
          || string_in 
          || '" using "' 
          || outer_delim_in 
          || '-' 
          || inner_delim_in 
          || '"'); 
     l_items := string_to_list (string_in, outer_delim_in, inner_delim_in); 


     FOR outer_index IN 1 .. l_items.COUNT 
     LOOP 
     DBMS_OUTPUT.put_line( 'List ' 
           || outer_index 
           || ' contains ' 
           || l_items (outer_index).COUNT 
           || ' elements'); 

     FOR inner_index IN 1 .. l_items (outer_index).COUNT 
     LOOP 
      DBMS_OUTPUT.put_line( '> Value ' 
           || inner_index 
           || ' = ' 
           || l_items (outer_index) (inner_index)); 
     END LOOP; 
     END LOOP; 
    END display_list; 

    PROCEDURE display_list (string_in  IN VARCHAR2 
         , outer_delim_in IN VARCHAR2 
         , name_delim_in IN VARCHAR2 
         , inner_delim_in IN VARCHAR2 
         ) 
    IS 
     l_items named_nested_items_tt; 
     l_index maxvarchar2_t; 
    BEGIN 
     DBMS_OUTPUT.put_line( 'Parse "' 
          || string_in 
          || '" using "' 
          || outer_delim_in 
          || '-' 
          || name_delim_in 
          || '-' 
          || inner_delim_in 
          || '"'); 
     l_items := 
     string_to_list (string_in 
         , outer_delim_in 
         , name_delim_in 
         , inner_delim_in 
         ); 

     l_index := l_items.FIRST; 

     WHILE (l_index IS NOT NULL) 
     LOOP 
     DBMS_OUTPUT.put_line( 'List "' 
           || l_index 
           || '" contains ' 
           || l_items (l_index).COUNT 
           || ' elements'); 

     FOR inner_index IN 1 .. l_items (l_index).COUNT 
     LOOP 
      DBMS_OUTPUT.put_line( '> Value ' 
           || inner_index 
           || ' = ' 
           || l_items (l_index) (inner_index)); 
     END LOOP; 

     l_index := l_items.NEXT (l_index); 
     END LOOP; 
    END display_list; 

    PROCEDURE show_variations 
    IS 
     PROCEDURE show_header (title_in IN VARCHAR2) 
     IS 
     BEGIN 
     DBMS_OUTPUT.put_line (RPAD ('=', 60, '=')); 
     DBMS_OUTPUT.put_line (title_in); 
     DBMS_OUTPUT.put_line (RPAD ('=', 60, '=')); 
     END show_header; 
    BEGIN 
     show_header ('Single Delimiter Lists'); 
     display_list ('a,b,c'); 
     display_list ('a;b;c', ';'); 
     display_list ('a,,b,c'); 
     display_list (',,b,c,,'); 

     show_header ('Nested Lists'); 
     display_list ('a,b,c,d|1,2,3|x,y,z', '|', ','); 

     show_header ('Named, Nested Lists'); 
     display_list ('letters:a,b,c,d|numbers:1,2,3|names:steven,george' 
        , '|' 
        , ':' 
        , ',' 
        ); 
    END; 

    FUNCTION nested_eq (list1_in IN items_tt 
        , list2_in IN items_tt 
        , nulls_eq_in IN BOOLEAN 
        ) 
     RETURN BOOLEAN 
    IS 
     l_return BOOLEAN := list1_in.COUNT = list2_in.COUNT; 
     l_index PLS_INTEGER := 1; 
    BEGIN 
     WHILE (l_return AND l_index IS NOT NULL) 
     LOOP 
     l_return := list1_in (l_index) = list2_in (l_index); 
     l_index := list1_in.NEXT (l_index); 
     END LOOP; 

     RETURN l_return; 
    EXCEPTION 
     WHEN NO_DATA_FOUND 
     THEN 
     RETURN FALSE; 
    END nested_eq; 
END; 
/

Answer 4

簡單代碼

 
    create or replace function get_token(text_is varchar2, token_in number, delim_is varchar2 := ';') return varchar2 is 
     text_ls varchar2(2000); 
     spos_ln number; 
     epos _ln number; 
    begin 
     text_ls := delim_is || text_is || rpad(delim_is, token_in, delim_is); 
     spos_ln := instr(text_ls, delim_is, 1, token_in); 
     epos_ln := instr(text_ls, delim_is, 1, token_in+1); 
     return substr(text_ls, spos_ln+1, epos_ln-spos_ln-1); 
    end get_token; 

Answer 5

我們永遠無法用完做同樣的替代品事情不同，對吧？ 最近我發現這是非常方便的：

DECLARE 
    BAR VARCHAR2 (200) := '1,2,3'; 
BEGIN 
    FOR FOO IN ( SELECT REGEXP_SUBSTR (BAR, 
             '[^,]+', 
             1, 
             LEVEL) 
          TXT 
        FROM DUAL 
       CONNECT BY REGEXP_SUBSTR (BAR, 
             '[^,]+', 
             1, 
             LEVEL) 
          IS NOT NULL) 
    LOOP 
     DBMS_OUTPUT.PUT_LINE (FOO.TXT); 
    END LOOP; 
END; 

輸出：

1 
2 
3 

Answer 6

declare 
    v_str varchar2(100) := '1,2,3,4,6,7,8,9,0,'; 
    v_str1 varchar2(100); 
    v_comma_pos number := 0;  
    v_start_pos number := 1; 
begin    
    loop   
    v_comma_pos := instr(v_str,',',v_start_pos); 
    v_str1 := substr(v_str,v_start_pos,(v_comma_pos - v_start_pos)); 
    dbms_output.put_line(v_str1);  
    if v_comma_pos = 0 then  
    v_str1 := substr(v_str,v_start_pos); 
    dbms_output.put_line(v_str1);  
    exit; 
    end if;  
    v_start_pos := v_comma_pos + 1; 
    if v_comma_pos = 0 then  
    exit; 
    end if;  
    end loop; 
end; 

Answer 7

我一直在尋找一個類似的解決方案，我不得不多字節字符（連字符，空格，下劃線）用逗號分隔的列表。所以dbms_utility.comma_to_table沒有爲我工作。

declare 
    curr_val varchar2 (255 byte); 
    input_str varchar2 (255 byte); 
    remaining_str varchar2 (255 byte); 
begin 
    remaining_str := input_str || ',dummy'; -- this value won't output 
    while (regexp_like (remaining_str, '.+,.+')) 
    loop 
    curr_val := substr (remaining_str, 1, instr (remaining_str, ',') - 1); 
    remaining_str = substr (remaining_str, instr (remaining_str, ',') + 1); 
    dbms_output.put_line (curr_val); 
    end loop; 
end; 

這不是專家的回答，所以我希望有人會改善這個答案。

Answer 8

另一種可能性是：

create or replace FUNCTION getNth (
    input varchar2, 
    nth number 
) RETURN varchar2 AS 
    nthVal varchar2(80); 
BEGIN 
    with candidates (s,e,n) as (
     select 1, instr(input,',',1), 1 from dual 
     union all 
     select e+1, instr(input,',',e+1), n+1 
     from candidates where e > 0) 
    select substr(input,s,case when e > 0 then e-s else length(input) end) 
    into nthVal 
    from candidates where n=nth; 
    return nthVal; 
END getNth; 

它的運行有點太昂貴，因爲它的每一個來電者要求在那裏的項目之一時間計算完成分割...

Answer 9

我知道上粘貼URL，而不解釋堆棧溢出皺眉，但這個特定頁面有幾個真正的好選擇：

http://www.oratechinfo.co.uk/delimited_lists_to_collections.html

我特別喜歡這一個，它的分隔列表轉換成一個臨時表你可以對運行查詢：

/* Create the output TYPE, here using a VARCHAR2(100) nested table type */ 

SQL> CREATE TYPE test_type AS TABLE OF VARCHAR2(100); 
    2/

Type created. 

/* Now, create the function.*/ 

SQL> CREATE OR REPLACE FUNCTION f_convert(p_list IN VARCHAR2) 
    2 RETURN test_type 
    3 AS 
    4 l_string  VARCHAR2(32767) := p_list || ','; 
    5 l_comma_index PLS_INTEGER; 
    6 l_index  PLS_INTEGER := 1; 
    7 l_tab   test_type := test_type(); 
    8 BEGIN 
    9 LOOP 
10  l_comma_index := INSTR(l_string, ',', l_index); 
11  EXIT WHEN l_comma_index = 0; 
12  l_tab.EXTEND; 
13  l_tab(l_tab.COUNT) := SUBSTR(l_string, l_index, l_comma_index - l_index); 
14  l_index := l_comma_index + 1; 
15 END LOOP; 
16 RETURN l_tab; 
17 END f_convert; 
18/

Function created. 

---

/* Prove it works */ 

SQL> SELECT * FROM TABLE(f_convert('AAA,BBB,CCC,D')); 

COLUMN_VALUE 
-------------------------------------------------------------------------------- 
AAA 
BBB 
CCC 
D 

4 rows selected. 

Answer 10

這裏是另一種更容易的選擇

select to_number(column_value) as IDs from xmltable('1,2,3,4,5'); 

Answer 11

使用pipelined table function：

SQL> CREATE OR REPLACE TYPE test_type 
    2 AS 
    3 TABLE OF VARCHAR2(100) 
    4/

Type created. 

SQL> CREATE OR REPLACE FUNCTION comma_to_table(
    2  p_list IN VARCHAR2) 
    3 RETURN test_type PIPELINED 
    4 AS 
    5 l_string LONG := p_list || ','; 
    6 l_comma_index PLS_INTEGER; 
    7 l_index PLS_INTEGER := 1; 
    8 BEGIN 
    9 LOOP 
10  l_comma_index := INSTR(l_string, ',', l_index); 
11  EXIT 
12 WHEN l_comma_index = 0; 
13  PIPE ROW (TRIM(SUBSTR(l_string, l_index, l_comma_index - l_index))); 
14  l_index := l_comma_index        + 1; 
15 END LOOP; 
16 RETURN; 
17 END comma_to_table; 
18/

Function created. 

讓我們來看看輸出：

SQL> SELECT * 
    2 FROM TABLE(comma_to_table('12 3,456,,,,,abc,def')) 
    3/

COLUMN_VALUE 
------------------------------------------------------------------------------ 
12 3 
456 




abc 
def 

8 rows selected. 

SQL> 

Answer 12

您可以使用替換功能來取代逗號容易。 爲了做這個 -

在SQL Server（的Transact-SQL）REPLACE函數的語法爲：
REPLACE（字符串，string_to_replace，replacement_string）

參數或參數

字符串：從其中一系列字符將被另一組字符替換的源字符串。
string_to_replace：將在string1中搜索的字符串。
replacement_string：替換字符串。所有出現的string_to_replace將被string1中的replacement_string替換。
注：

Replace函數執行替換不是 區分大小寫。所以string_to_replace的所有出現將被 替換無論replacement_string string_to_replace的箱子或replacement_string

例如：
SELECT REPLACE（'卡皮爾，拉吉，chouhan'， ''， '' ）來自DUAL;
結果：卡皮拉吉chouhan

SELECT REPLACE（'我住在印度'， ''， ' - '）從DUAL;
結果：I-住在印度

SELECT REPLACE（'facebook.com'， '面子'， '朋友'）從DUAL;
結果：friendsbook。com

我希望它對你有用。

Answer 13

TYPE string_aa IS TABLE OF VARCHAR2(32767) INDEX BY PLS_INTEGER; 

FUNCTION string_to_list(p_string_in IN VARCHAR2) 
    RETURN string_aa 
    IS 
     TYPE ref_cursor IS ref cursor; 
     l_cur ref_cursor; 
     l_strlist string_aa; 
     l_x  PLS_INTEGER; 
    BEGIN  
     IF p_string_in IS NOT NULL THEN 
     OPEN l_cur FOR 
      SELECT regexp_substr(p_string_in,'[^,]+', 1, level) FROM dual 
      CONNECT BY regexp_substr(p_string_in, '[^,]+', 1, level) IS NOT NULL;  
     l_x := 1; 
     LOOP 
      FETCH l_cur INTO l_strlist(l_x); 
      EXIT WHEN l_cur%notfound; 
      -- excludes NULL items e.g. 1,2,,,,5,6,7 
      l_x := l_x + 1; 
     END LOOP; 
     END IF; 
     RETURN l_strlist; 
    END string_to_list; 

Answer 14

declare 
seprator varchar2(1):=','; 
dosweeklist varchar2(4000):='a,b,c'; 
begin 
for i in (SELECT SUBSTR(dosweeklist, 
         case when level=1 then 1 else INSTR(dosweeklist,seprator,1,LEVEL-1)+1 end, 
         NVL(NULLIF(INSTR(dosweeklist,seprator,1,LEVEL),0),length(dosweeklist)+1) - case when level=1 then 1 else INSTR(dosweeklist,seprator,1,LEVEL-1)+1 end) dat 
      FROM dual 
      CONNECT BY LEVEL <= LENGTH(dosweeklist) - LENGTH(REPLACE(dosweeklist,seprator,'')) +1) 
loop 
dbms_output.put_line(i.dat); 
end loop; 
end; 
/

因此選擇查詢只在for循環可以做的伎倆，通過更換dosweeklist作爲分隔字符串和seprator作爲分隔符的。

讓我們來看看輸出

a 

b 

c