oracle - 如何将 Oracle 的 LISTAGG 函数与多值一起使用？

Question

我有一个“项目”表，如下所示:

ITEM_NO     ITEM_NAME   
1               Book   
2               Pen   
3               Sticky Notes   
4               Ink   
5               Corrector   
6               Ruler  

在另一个“EMP_ITEMS”表中，我有以下内容:

EMPLOYEE        ITEMS_LIST   
 John           1,2   
 Mikel          5   
 Sophia         2,3,6  
 William        3,4   
 Daniel         null   
 Michael        6  

输出必须是这样的:

EMPLOYEE        ITEMS_LIST      ITEM_NAME   
John            1,2             Book,Pen   
Mikel           5               Corrector   
Sophia          2,3,6           Pen,Sticky Notes,Ruler   
William         3,4             Sticky Notes,Ink   
Daniel          null            null   
Michael         6               Ruler

我使用了以下查询:

SELECT e.EMPLOYEE,e.ITEMS_LIST, LISTAGG(i.ITEM_NAME, ',') WITHIN GROUP (ORDER BY i.ITEM_NAME) ITEM_DESC 
 FROM EMP_ITEMS e  
INNER JOIN ITEMS i ON i.ITEM_NO = e.ITEMS_LIST 
GROUP BY e.EMPLOYEE,e.ITEMS_LIST;

但是有一个错误:

ORA-01722: invalid number

Answer 1

But there is an error: ORA-01722: invalid number

那是因为您的 ITEMS_LIST是一个由数字和逗号字符组成的字符串，实际上不是数字列表，您正在尝试将单个项目编号与项目列表进行比较。

而是将其视为字符串以查找子字符串匹配。为此，您需要将字符串括在分隔符中，并比较其中一个是否是另一个的子字符串:

SQL Fiddle

Oracle 11g R2 架构设置 :

CREATE TABLE Items ( ITEM_NO, ITEM_NAME ) As
SELECT 1, 'Book' FROM DUAL UNION ALL
SELECT 2, 'Pen' FROM DUAL UNION ALL
SELECT 3, 'Sticky Notes' FROM DUAL UNION ALL
SELECT 4, 'Ink' FROM DUAL UNION ALL
SELECT 5, 'Corrector' FROM DUAL UNION ALL
SELECT 6, 'Ruler' FROM DUAL;

CREATE TABLE emp_items ( EMPLOYEE, ITEMS_LIST ) AS
SELECT 'John', '1,2' FROM DUAL UNION ALL
SELECT 'Mikel', '5' FROM DUAL UNION ALL
SELECT 'Sophia', '3,2,6' FROM DUAL UNION ALL
SELECT 'William', '3,4' FROM DUAL UNION ALL
SELECT 'Daniel', null FROM DUAL UNION ALL
SELECT 'Michael', '6' FROM DUAL;

查询 1 :

SELECT e.employee,
       e.items_list,
       LISTAGG( i.item_name, ',' )
         WITHIN GROUP (
           ORDER BY INSTR( ','||e.items_list||',', ','||i.item_no||',' )
         ) AS item_names
FROM   emp_items e
       LEFT OUTER JOIN
       items i
       ON ( ','||e.items_list||',' LIKE '%,'||i.item_no||',%' )
GROUP BY e.employee, e.items_list

Results :

| EMPLOYEE | ITEMS_LIST |             ITEM_NAMES |
|----------|------------|------------------------|
|     John |        1,2 |               Book,Pen |
|    Mikel |          5 |              Corrector |
|   Daniel |     (null) |                 (null) |
|   Sophia |      3,2,6 | Sticky Notes,Pen,Ruler |
|  Michael |          6 |                  Ruler |
|  William |        3,4 |       Sticky Notes,Ink |