我正在尝试对以 1 开头且连续为 0 的行进行分组，并在遇到另一个 1 或 2 时停止分组。
这里是一个例子：（“组”列是我期望看到的）
+-----+------+-------+
| seq | data | group |
+-----+------+-------+
| 1 | 1 | 1 |
| 2 | 0 | 1 |
| 3 | 0 | 1 |
| 4 | 0 | 1 |
| 5 | 2 | |
| 6 | 2 | |
| 7 | 1 | 2 |
| 8 | 0 | 2 |
| 9 | 0 | 2 |
| 10 | 1 | 3 |
| 11 | 0 | 3 |
| 12 | 0 | 3 |
| 13 | 2 | |
| 14 | 0 | |
| 15 | 0 | |
| 16 | 0 | |
| 17 | 0 | |
| 18 | 0 | |
| 19 | 2 | |
| 20 | 2 | |
| 21 | 1 | 4 |
| 22 | 0 | 4 |
| 23 | 0 | 4 |
| 24 | 0 | 4 |
| 25 | 2 | |
| 26 | 2 | |
| 27 | 0 | |
| 28 | 1 | 5 |
| 29 | 0 | 5 |
| 30 | 0 | 5 |
| 31 | 0 | 5 |
| 32 | 1 | 6 |
| 33 | 0 | 6 |
| 34 | 0 | 6 |
| 35 | 0 | 6 |
| 36 | 0 | 6 |
| 37 | 2 | |
| 38 | 0 | |
| 39 | 0 | |
| 40 | 0 | |
| 41 | 0 | |
| 42 | 0 | |
| 43 | 0 | |
| 44 | 0 | |
| 45 | 0 | |
| 46 | 2 | |
| 47 | 2 | |
| 48 | 2 | |
+-----+------+-------+
我已经尝试使用 coalesce 来实现它，但这就是我所拥有的：
select seq, data, coalesce((select sum(data) +1
from mytable pre
where pre.seq <= mytable.seq and pre.data = 1),0) as s1
from mytable
+-----+------+-------+
| seq | data | group |
+-----+------+-------+
| 1 | 1 | 2 |
| 2 | 0 | 2 |
| 3 | 0 | 2 |
| 4 | 0 | 2 |
| 5 | 2 | 2 |
| 6 | 2 | 2 |
| 7 | 1 | 3 |
| 8 | 0 | 3 |
| 9 | 0 | 3 |
| 10 | 1 | 4 |
| 11 | 0 | 4 |
| 12 | 0 | 4 |
| 13 | 2 | 4 |
| 14 | 0 | 4 |
| 15 | 0 | 4 |
| 16 | 0 | 4 |
| 17 | 0 | 4 |
| 18 | 0 | 4 |
| 19 | 2 | 4 |
| 20 | 2 | 4 |
| 21 | 1 | 5 |
| 22 | 0 | 5 |
| 23 | 0 | 5 |
| 24 | 0 | 5 |
| 25 | 2 | 5 |
| 26 | 2 | 5 |
| 27 | 0 | 5 |
| 28 | 1 | 6 |
| 29 | 0 | 6 |
| 30 | 0 | 6 |
| 31 | 0 | 6 |
| 32 | 1 | 7 |
| 33 | 0 | 7 |
| 34 | 0 | 7 |
| 35 | 0 | 7 |
| 36 | 0 | 7 |
| 37 | 2 | 7 |
| 38 | 0 | 7 |
| 39 | 0 | 7 |
| 40 | 0 | 7 |
| 41 | 0 | 7 |
| 42 | 0 | 7 |
| 43 | 0 | 7 |
| 44 | 0 | 7 |
| 45 | 0 | 7 |
| 46 | 2 | 7 |
| 47 | 2 | 7 |
| 48 | 2 | 7 |
+-----+------+-------+
遇到1或2我想停止分组，你能帮我解决这个问题吗？谢谢
++
我有一个类似的任务，就是从下到上分组，但条件略有不同。
我需要在数据以“2”开头时对数据进行分组，并在遇到 0 或 1 时关闭该组，但也需要将它们包含在组中（0 或 1）。以下是预期的输出。
+-----+------+-------+ | seq | data | group | +-----+------+-------+ | 1 | 1 | 11 | | 2 | 0 | 11 | | 3 | 0 | 11 | | 4 | 0 | 11 | | 5 | 2 | 11 | | 6 | 2 | 10 | | 7 | 1 | | | 8 | 0 | | | 9 | 0 | | | 10 | 1 | 9 | | 11 | 0 | 9 | | 12 | 0 | 9 | | 13 | 2 | 9 | | 14 | 0 | 8 | | 15 | 0 | 8 | | 16 | 0 | 8 | | 17 | 0 | 8 | | 18 | 0 | 8 | | 19 | 2 | 8 | | 20 | 2 | 7 | | 21 | 1 | 6 | | 22 | 0 | 6 | | 23 | 0 | 6 | | 24 | 0 | 6 | | 25 | 2 | 6 | | 26 | 2 | 5 | | 27 | 0 | | | 28 | 1 | | | 29 | 0 | | | 30 | 0 | | | 31 | 0 | | | 32 | 1 | 4 | | 33 | 0 | 4 | | 34 | 0 | 4 | | 35 | 0 | 4 | | 36 | 0 | 4 | | 37 | 2 | 4 | | 38 | 0 | 3 | | 39 | 0 | 3 | | 40 | 0 | 3 | | 41 | 0 | 3 | | 42 | 0 | 3 | | 43 | 0 | 3 | | 44 | 0 | 3 | | 45 | 0 | 3 | | 46 | 2 | 3 | | 47 | 2 | 2 | | 48 | 2 | 1 | +-----+------+-------+
我使用了与@shawnt00 的回答类似的方法，下面是我得到的。
它给出了我期望看到的结果，但我想尽可能避免左外连接。有什么方法可以使这个查询干净吗？
with g1 as (
select *,
count(case when data = 2 then 1 end) over (order by seq desc) as grp
from mytable
), g2 as (
select *,
count(case when data > 0 then 1 end) over (partition by grp order by seq desc) as grp2
from g1
)
select curr.seq, curr.data, curr.grp,
CASE WHEN curr.data = 1 AND next.grp2 = 1 THEN 1
ELSE curr.grp2 END AS grp2
from g2 curr left outer join g2 next on curr.seq + 1 = next.seq
-- where grp2 = 1;
order by curr.seq
;
+-----+------+-----+------+
| seq | data | grp | grp2 |
+-----+------+-----+------+
| 1 | 1 | 11 | 1 |
| 2 | 0 | 11 | 1 |
| 3 | 0 | 11 | 1 |
| 4 | 0 | 11 | 1 |
| 5 | 2 | 11 | 1 |
| 6 | 2 | 10 | 1 |
| 7 | 1 | 9 | 3 |
| 8 | 0 | 9 | 2 |
| 9 | 0 | 9 | 2 |
| 10 | 1 | 9 | 1 |
| 11 | 0 | 9 | 1 |
| 12 | 0 | 9 | 1 |
| 13 | 2 | 9 | 1 |
| 14 | 0 | 8 | 1 |
| 15 | 0 | 8 | 1 |
| 16 | 0 | 8 | 1 |
| 17 | 0 | 8 | 1 |
| 18 | 0 | 8 | 1 |
| 19 | 2 | 8 | 1 |
| 20 | 2 | 7 | 1 |
| 21 | 1 | 6 | 1 |
| 22 | 0 | 6 | 1 |
| 23 | 0 | 6 | 1 |
| 24 | 0 | 6 | 1 |
| 25 | 2 | 6 | 1 |
| 26 | 2 | 5 | 1 |
| 27 | 0 | 4 | 3 |
| 28 | 1 | 4 | 3 |
| 29 | 0 | 4 | 2 |
| 30 | 0 | 4 | 2 |
| 31 | 0 | 4 | 2 |
| 32 | 1 | 4 | 1 |
| 33 | 0 | 4 | 1 |
| 34 | 0 | 4 | 1 |
| 35 | 0 | 4 | 1 |
| 36 | 0 | 4 | 1 |
| 37 | 2 | 4 | 1 |
| 38 | 0 | 3 | 1 |
| 39 | 0 | 3 | 1 |
| 40 | 0 | 3 | 1 |
| 41 | 0 | 3 | 1 |
| 42 | 0 | 3 | 1 |
| 43 | 0 | 3 | 1 |
| 44 | 0 | 3 | 1 |
| 45 | 0 | 3 | 1 |
| 46 | 2 | 3 | 1 |
| 47 | 2 | 2 | 1 |
| 48 | 2 | 1 | 1 |
+-----+------+-----+------+
标记行两次。首先计算以 1 开头的块/运行。现在在每个块/运行中，将以非零开头的运行分开并编号。 “分组”行必须是第二个列表中的第一行。
with g1 as (
select *,
count(case when data = 1 then 1 end) over (order by seq) as grpA,
count(case when data = 2 then 1 end) over (order by seq desc) as grpD
from T
), g2 as (
select *,
count(case when data <> 0 then 1 end) over (partition by grpA order by seq) as grpA2,
count(case when data = 1 then 1 end) over (partition by grpD order by seq desc
rows between unbounded preceding and 1 preceding) as grpD2
from g1
)
select seq, data,
case when grpA2 = 1 then grpA end as groupA,
case when grpD2 = 1 then grpD end as groupD
from g2;
这应该比自连接更有效率。
使用子查询和
leadidwith cte as (
select t.*, (select count(*) from tbl t1 where t1.seq <= t.seq and t1.data > 0) r
from tbl t
),
runs as (
select c.seq, c.data, c.r, case when (c.data = 1 and lead(c.data, 1) over (order by c.seq) = 0) or
(c.data = 0 and not exists (select 1 from cte c1 where c1.r = c.r and c1.data > 1))
then c.r else 0 end r1
from cte c
)
select r.seq, r.data, case when r.r1 = 0 then null else (select count(distinct r1.r1) from runs r1 where r1.seq <= r.seq and r1.r1 > 0) end from runs r