SQL 合并行而不是 UNION ALL

Question

我正在执行 UNION ALL 以获得如下 table 中所示的结果。这种方法导致有不必要的行。 DESK、SEGMENT、SUPERVISOR这三列是独立的，没有任何关系。

代码

SELECT ID, DESK, '' as SEGMENT, '' as SUPERVISOR FROM myTable1 
UNION ALL 
SELECT ID, '' AS DESK, SEGMENT, '' as SUPERVISOR FROM myTable2 
UNION ALL 
SELECT ID, '' AS DESK, '' as SEGMENT, SUPERVISOR FROM myTable3

结果：

+------+------------+---------+------------+
| ID   | DESK       | SEGMENT | SUPERVISOR | TOTAL ENTRIES
+------+------------+---------+------------+
| 4782 | OIL & GAS  |         |            |  23
+------+------------+---------+------------+
| 4782 | AUTOMOTIVE |         |            |  23
+------+------------+---------+------------+
| 4782 |            | GLOBAL  |            |  23
+------+------------+---------+------------+
| 4782 |            |         | DANIEL     |  23
+------+------------+---------+------------+
| 4782 |            |         | JAMES      |  23
+------+------------+---------+------------+

如何查询得到以下结果？

预期结果：

+------+------------+---------+------------+
| ID   | DESK       | SEGMENT | SUPERVISOR | TOTAL ENTRIES
+------+------------+---------+------------+
| 4782 | OIL & GAS  | GLOBAL  | DANIEL     |  23
+------+------------+---------+------------+
| 4782 | AUTOMOTIVE |         | JAMES      |  23
+------+------------+---------+------------+

Answer 1

你可以试试这个：

SELECT table1.ID, table1.DESK, table2.SEGMENT, (select SUPERVISOR from (select SUPERVISOR, ROWNUM AS RN FROM table3) WHERE RN = 1) SUPERVISOR
FROM table1 JOIN table2 on table1.ID = table2.ID
WHERE table1.DESK = 'OIL & GAS'
UNION ALL
SELECT table1.ID, table1.DESK, null SEGMENT, (select SUPERVISOR from (select SUPERVISOR, ROWNUM AS RN FROM table3) WHERE RN = 2) SUPERVISOR
FROM table1 JOIN table2 on table1.ID = table2.ID
WHERE table1.DESK = 'AUTOMOTIVE'

https://dbfiddle.uk/?rdbms=oracle_11.2&fiddle=c5594bb1d99579611d2669f6bab675a2

Answer 2

您可以尝试如下查询。我不知道 23 是从哪里来的，所以我没有将它考虑到查询中，但是如果它是三个表之一中的列，可以使用类似的逻辑将它添加到结果中。

查询

WITH
    table1 (id, desk)
    AS
        (SELECT 4782, 'OIL & GAS' FROM DUAL
         UNION ALL
         SELECT 4782, 'AUTOMOTIVE' FROM DUAL),
    table2 (id, segment) AS (SELECT 4782, 'GLOBAL' FROM DUAL),
    table3 (id, supervisor)
    AS
        (SELECT 4782, 'DANIEL' FROM DUAL
         UNION ALL
         SELECT 4782, 'JAMES' FROM DUAL)
SELECT *
  FROM (SELECT t1.id,
               CASE WHEN t1.desk = LAG (t1.desk) OVER (ORDER BY t1.desk) THEN NULL ELSE t1.desk END
                   AS desk,
               CASE
                   WHEN t2.segment = LAG (t2.segment) OVER (ORDER BY t2.segment) THEN NULL
                   ELSE t2.segment
               END
                   AS segment,
               CASE
                   WHEN t3.supervisor = LAG (t3.supervisor) OVER (ORDER BY t3.supervisor) THEN NULL
                   ELSE t3.supervisor
               END
                   AS supervisor
          FROM table1 t1, table2 t2, table3 t3
         WHERE t1.id = t2.id AND t1.id = t3.id)
 WHERE desk IS NOT NULL OR segment IS NOT NULL OR supervisor IS NOT NULL;

结果

     ID          DESK    SEGMENT    SUPERVISOR
_______ _____________ __________ _____________
   4782 AUTOMOTIVE    GLOBAL     DANIEL
   4782 OIL & GAS                JAMES

Answer 3

对于这三个表，您可以使用 ROW_NUMBER() 由 ID 列分区的分析函数以及 FULL OUTER JOIN ：

SELECT NVL(NVL(t2.ID,t3.ID),t1.ID) AS ID, desk, segment, supervisor 
  FROM ( SELECT t1.*, ROW_NUMBER() OVER (PARTITION BY ID ORDER BY 0) AS rn FROM myTable1 t1 ) t1
  FULL JOIN ( SELECT t2.*, ROW_NUMBER() OVER (PARTITION BY ID ORDER BY 0) AS rn FROM myTable2 t2 ) t2
    ON t2.ID = t1.ID AND t2.rn = t1.rn
  FULL JOIN ( SELECT t3.*, ROW_NUMBER() OVER (PARTITION BY ID ORDER BY 0) AS rn FROM myTable3 t3 ) t3
    ON t3.ID = t1.ID AND t3.rn = t1.rn;


ID   DESK        SEGMENT  SUPERVISOR
---- ----------  -------  ----------
4782 AUTOMOTIVE  GLOBAL   JAMES
4782 OIL & GAS            DANIEL

Demo

P.S：我留下了 ORDER BY 0，因为 ORDER BY 选项对于 ROW_NUMBER() 是强制性的，您可以用适合您的列或标识符替换零。

SQL 合并行而不是 UNION ALL

SQL Merge rows instead of UNION ALL

sql

oracle

union

union-all

查询

结果