テーブル内の文字列（1列）として複数の行を返すサブクエリを選択します（OracleSQL）

SQLフィドル

Oracle11gR2スキーマのセットアップ ：

CREATE TABLE Product ( Product_No, Column1, Column2 ) AS
SELECT 1, 'A', 10 FROM DUAL UNION ALL
SELECT 2, 'B', 11 FROM DUAL UNION ALL
SELECT 3, 'C', 12 FROM DUAL
/
CREATE TABLE Inventory ( Product_No, Inventory_No, ColumnA, ColumnB, ColumnC ) AS
SELECT 1, 1, 'ABC',  20,  30 FROM DUAL UNION ALL
SELECT 1, 2, 'DDD',  30,  50 FROM DUAL UNION ALL
SELECT 2, 1, 'EFG',  60,  70 FROM DUAL UNION ALL
SELECT 2, 2, 'CDE',  99, 100 FROM DUAL UNION ALL
SELECT 3, 3, 'EFF', 120,  30 FROM DUAL
/

クエリ1 ：

SELECT p.*, i.ColumnX
FROM   Product p
       LEFT OUTER JOIN
       ( SELECT Product_no,
                LISTAGG(
                  ColumnA || '-' || ColumnB || '-' || ColumnC,
                  ','
                ) WITHIN GROUP ( ORDER BY Inventory_no )
                AS ColumnX
         FROM   Inventory
         GROUP BY Product_No
       ) i
       ON ( p.product_no = i.product_no )

結果 ：

| PRODUCT_NO | COLUMN1 | COLUMN2 |              COLUMNX |
|------------|---------|---------|----------------------|
|          1 |       A |      10 |  ABC-20-30,DDD-30-50 |
|          2 |       B |      11 | EFG-60-70,CDE-99-100 |
|          3 |       C |      12 |           EFF-120-30 |