mysql - Sql 使用比 from-in to-in 命令更小的命令

Question

您假设在 posts 表中我有 10 条记录，其中包含 deleted 列，例如:

id    title     deleted
1     a         true
2     a         true
3     a         false
4     a         false
5     a         false
6     a         false
7     a         false
8     a         false
9     a         true
10    a         true

id 3 到 8 中的 deleted 列为 false

我想选择从 3 到 deleted 列为 true 之间的所有记录，以查找其中 false 的记录数，

例如

select * from posts where id = 10 (to find which id is true)

我想要这个结果:

3,4,5,6,7,8

Answer 1

要查找已删除的第一个 id (>3)，您可以使用:

SELECT id FROM posts WHERE deleted = 'true' AND id > 3 ORDER BY id LIMIT 1

这将导致9。使用上面作为子查询，查找 3 到 8 之间的所有行:

SELECT * 
FROM posts 
WHERE id >= 3 
  AND id < (SELECT id FROM posts WHERE deleted = 'true' AND id > 3 ORDER BY id LIMIT 1)

如果 id > 3 之后没有任何 deleted = 'true' 行，子查询将返回 NULL，因此要添加案例:

SELECT * 
FROM posts 
WHERE id >= 3 
  AND (
    id < (SELECT id FROM posts WHERE deleted = 'true' AND id > 3 ORDER BY id LIMIT 1)
    OR (SELECT id FROM posts WHERE deleted = 'true' AND id > 3 ORDER BY id LIMIT 1) IS NULL
  )