SQlite

Question

我有一个 SQlite 数据库，其中有两个 table 具有相同的模式。它们包含来自两个不同来源的学生考试数据。

+────────+─────────────+─────────────────+──────────────────────────────────────+─────────────+────────+
| rowid  | student_id  | level           | name                                 | start       | grade  |
+────────+─────────────+─────────────────+──────────────────────────────────────+─────────────+────────+
| 0      | 10001       | Diploma         | Business                             | 2022-04-01  | Pass   |
| 1      | 10001       | Standard Grade  | Mathematics                          | 2013-08-06  | Pass   |
| 2      | 10002       | Intermediate 1  | Hospitality: Practical Cookery       | 2013-08-06  | Pass   |
| 3      | 10003       | Unlevelled      | Elementary Food Hygiene Plus         | 2016-04-28  | Pass   |
| 4      | 10004       | SCQF Level 4    | Employability Award                  | 2015-06-18  | Pass   |
| 5      | 10004       | Level 1         | SVQ in Food Preparation and Cooking  | 2015-06-18  | Pass   |
| 6      | 10004       | Standard Grade  | Geography                            | 2013-08-06  | Fail   |
| 7      | 10005       | Standard Grade  | Social & Vocational Skills           | 2013-08-06  | Pass   |
| 8      | 10006       | Standard Grade  | Art and Design                       | 2013-08-06  | Pass   |
| 9      | 10006       | Standard Grade  | English                              | 2013-08-06  | Pass   |
| 10     | 10007       | Intermediate 1  | Chemistry                            | 2013-08-06  | Pass   |
+────────+─────────────+─────────────────+──────────────────────────────────────+─────────────+────────+

Table A 已经使用下面的 SQL 查询进行过滤，以过滤掉学生不及格然后重新参加并通过的考试。它使用 EXCEPT 删除先前失败的尝试，留下新的剩余通行证。

    query_A = """
        SELECT * FROM Table_A
        EXCEPT
        SELECT t1.*
        FROM Table_A t1
        WHERE t1.grade = 'Fail'
        AND EXISTS (
                SELECT *
                FROM Table_A t2
                WHERE (t2.student_id, t2.level, t2.name) = (t1.student_id, t1.level, t1.name)
                AND t1.grade <> t2.grade
            )
    """

Table B（虽然架构相同）包含不同的记录，一些但不是全部也存在于 Table A 中。

基本上，我想通过修改 query_A 语句从 Table_B 中删除 Table_B 中存在的任何记录，同时保留由 Table_A 创建的过滤器EXCEPT 命令。

Answer 1

I would like to remove any records that are present in Table_B from Table_A by modifying the query_A statement while retaining the filter on Table_A created by the EXCEPT command

再添加一个EXCEPT:

SELECT * FROM Table_A
EXCEPT
SELECT t1.*
FROM Table_A t1
WHERE t1.grade = 'Fail'
AND EXISTS (
  SELECT *
  FROM Table_A t2
  WHERE (t2.student_id, t2.level, t2.name) = (t1.student_id, t1.level, t1.name)
  AND t1.grade <> t2.grade
)
EXCEPT
SELECT * FROM Table_b;

SQlite - 修改 SQL 查询以删除在单独的 table 中找到的记录

SQlite - Modify SQL query to remove records found in separate table

sql