这有点棘手。您不能只比较相邻的行：您需要跟踪每个行序列的开始日期，以便可以将其与以下日期进行比较，并决定何时划分为新组。
这需要某种迭代过程。在sql中，这通常是通过递归查询实现的，幸运的是，snowflake支持递归查询
考虑：

with recursive 
    data as (
        select 
            t.*, 
            row_number() over(partition by userid, sessionid order by date) rn
        from mytable t
    ),
    cte as (
        select 
            userid, 
            sessionid,
            date start_session_date,
            date end_session_date
        from data
        where rn = 1
        union all
        select
            c.userid,
            c.sessionid,
            case when d.date > dateadd(minute, 30, c.start_session_date)
                then d.date
                else c.start_session_date
            end,
            d.date
        from cte c
        inner join data d 
            on  d.userid = c.userid
            and d.sessionid = c.sessionid 
            and d.rn = c.rn + 1 and 
    )
select 
    userid, 
    sessionid, 
    start_session_date, 
    max(end_session_date) end_session_date
from cte
group by userid, sessionid, start_session_date

第一个公共表表达式( data )枚举具有相同 userid 以及 sessionid 与 row_number() . 然后，第二个cte( cte )迭代地遍历行组，从第一个行开始，并根据需要创建新的组。最后一步是聚合。

此方法利用了雪花宽度_bucket函数，根据我生成的一些测试数据，似乎工作正常：

-- Get the min amd max timestamps for each userid, sessionid
WITH T1 AS (    
SELECT USERID, SESSIONID,MIN(DATE_TIME) MIN_DATE, MAX(DATE_TIME) MAX_DATE
FROM TEST_DATA
GROUP BY USERID, SESSIONID
),
--Get the number of 'buckets', for each userid/sessionid, to divide the data into by defining the time period
--Hardcoded here as MINUTE and 30
T2 AS (
SELECT USERID, SESSIONID, MIN_DATE, MAX_DATE, CEIL(DATEDIFF(MINUTE, MIN_DATE, MAX_DATE)/30,0) NUM_BUCKETS    
FROM T1
 ),
--Assign each record to the appropriate time period bucket
--WIDTH_BUCKET takes numeric parameters hence the conversion to epoch_seconds
T3 AS (
SELECT TD.USERID, TD.SESSIONID, TD.DATE_TIME
,width_bucket(DATE_PART(EPOCH_SECONDS,TD.DATE_TIME), DATE_PART(EPOCH_SECONDS,T2.MIN_DATE), DATE_PART(EPOCH_SECONDS,T2.MAX_DATE), T2.NUM_BUCKETS) as "TIME_GROUP"
FROM TEST_DATA TD
INNER JOIN T2 ON TD.USERID = T2.USERID AND TD.SESSIONID = T2.SESSIONID
)
--Get the min and make timestamps for each userid, sessionid and bucket combination
SELECT USERID, SESSIONID, MIN(DATE_TIME), MAX(DATE_TIME)
FROM T3
GROUP BY USERID, SESSIONID, TIME_GROUP
order BY USERID, SESSIONID, TIME_GROUP
LIMIT 10
 ;