无需代码中的任何连接即可获取“含糊不清定义的列”

Question

尝试执行以下脚本时出现“列定义不明确”错误：

INSERT INTO experience (id_, company, start_, end_, usr, position_) 
WITH exp_ AS (
    SELECT 0, 0, DATE'2013-04-30', NULL, 11, 'CEO' FROM DUAL UNION ALL
    SELECT 1, 0, DATE'2011-12-11', DATE'2013-04-30', 9, 'Administrator' FROM DUAL UNION ALL
    SELECT 2, 0, DATE'2013-04-30', DATE'2015-10-27', 6, 'Manager' FROM DUAL UNION ALL
    SELECT 3, 1, DATE'2014-11-04', NULL, 10, 'CEO' FROM DUAL UNION ALL
    SELECT 4, 1, DATE'2017-06-13', NULL, 13, 'CTO' FROM DUAL UNION ALL
    SELECT 5, 1, DATE'2010-04-22', DATE'2018-10-22', 1, 'Manager' FROM DUAL UNION ALL
    SELECT 6, 1, DATE'2019-08-26', NULL, 2, 'Trainer' FROM DUAL UNION ALL
    SELECT 7, 1, DATE'2006-02-27', DATE'2016-11-30', 6, 'Video Creator' FROM DUAL UNION ALL
    SELECT 8, 2, DATE'2012-04-30', DATE'2013-11-24', 5, 'CEO' FROM DUAL UNION ALL
    SELECT 9, 2, DATE'2013-01-10', NULL, 0, 'CEO' FROM DUAL UNION ALL
    SELECT 10, 2, DATE'2010-11-01', DATE'2017-01-01', 7, 'Video Creator' FROM DUAL UNION ALL
    SELECT 11, 2, DATE'2010-10-03', DATE'2018-03-01', 8, 'Commentator' FROM DUAL
)
SELECT * FROM exp_;

我在这里不使用任何JOIN，错误描述说，这是由于试图将两个具有重叠列名的表联接在一起引起的。

所以我为什么在这里买到它以及如何解决它？

Answer 1

您的列在CTE中没有名称。用名称定义它：

WITH exp_(id_, company, start_, end_, usr, position_) AS (

Here是db <>小提琴。

Answer 2

您需要为列指定别名。在第一个联合的子查询中就足够了：

INSERT INTO experience (id_, company, start_, end_, usr, position_) 
WITH exp_ AS (
    SELECT 
        0 id_, 
        0 company, 
        DATE'2013-04-30' start_, 
        NULL end_, 
        11 usr, 
        'CEO' position 
    FROM DUAL UNION ALL
    SELECT 1, 0, DATE'2011-12-11', DATE'2013-04-30', 9, 'Administrator' FROM DUAL UNION ALL
    SELECT 2, 0, DATE'2013-04-30', DATE'2015-10-27', 6, 'Manager' FROM DUAL UNION ALL
    SELECT 3, 1, DATE'2014-11-04', NULL, 10, 'CEO' FROM DUAL UNION ALL
    SELECT 4, 1, DATE'2017-06-13', NULL, 13, 'CTO' FROM DUAL UNION ALL
    SELECT 5, 1, DATE'2010-04-22', DATE'2018-10-22', 1, 'Manager' FROM DUAL UNION ALL
    SELECT 6, 1, DATE'2019-08-26', NULL, 2, 'Trainer' FROM DUAL UNION ALL
    SELECT 7, 1, DATE'2006-02-27', DATE'2016-11-30', 6, 'Video Creator' FROM DUAL UNION ALL
    SELECT 8, 2, DATE'2012-04-30', DATE'2013-11-24', 5, 'CEO' FROM DUAL UNION ALL
    SELECT 9, 2, DATE'2013-01-10', NULL, 0, 'CEO' FROM DUAL UNION ALL
    SELECT 10, 2, DATE'2010-11-01', DATE'2017-01-01', 7, 'Video Creator' FROM DUAL UNION ALL
    SELECT 11, 2, DATE'2010-10-03', DATE'2018-03-01', 8, 'Commentator' FROM DUAL
)
SELECT * FROM exp_;

对于您的用例，您还可以考虑使用insert all语法，它避免了多个union all：

insert all
into experience (id_, company, start_, end_, usr, position_)
    values(0, 0, date '2013-04-30', null, 11, 'CEO')
into experience (id_, company, start_, end_, usr, position_)
    values(1, 0, date '2011-12-11', date '2013-05-30', 9, 'Administrator')
...
select 1 from dual

Answer 3

仅当您删除CTE并直接使用UNION ALL插入行时，此语法才有效：

INSERT INTO experience (id_, company, start_, end_, usr, position_)
    SELECT 0, 0, DATE'2013-04-30', NULL, 11, 'CEO' FROM DUAL UNION ALL
    SELECT 1, 0, DATE'2011-12-11', DATE'2013-04-30', 9, 'Administrator' FROM DUAL UNION ALL
    SELECT 2, 0, DATE'2013-04-30', DATE'2015-10-27', 6, 'Manager' FROM DUAL UNION ALL
    SELECT 3, 1, DATE'2014-11-04', NULL, 10, 'CEO' FROM DUAL UNION ALL
    SELECT 4, 1, DATE'2017-06-13', NULL, 13, 'CTO' FROM DUAL UNION ALL
    SELECT 5, 1, DATE'2010-04-22', DATE'2018-10-22', 1, 'Manager' FROM DUAL UNION ALL
    SELECT 6, 1, DATE'2019-08-26', NULL, 2, 'Trainer' FROM DUAL UNION ALL
    SELECT 7, 1, DATE'2006-02-27', DATE'2016-11-30', 6, 'Video Creator' FROM DUAL UNION ALL
    SELECT 8, 2, DATE'2012-04-30', DATE'2013-11-24', 5, 'CEO' FROM DUAL UNION ALL
    SELECT 9, 2, DATE'2013-01-10', NULL, 0, 'CEO' FROM DUAL UNION ALL
    SELECT 10, 2, DATE'2010-11-01', DATE'2017-01-01', 7, 'Video Creator' FROM DUAL UNION ALL
    SELECT 11, 2, DATE'2010-10-03', DATE'2018-03-01', 8, 'Commentator' FROM DUAL

请参见demo。