期望分布table到return每个分片的结果，而不是聚合值

Question

有一个用户标签tabletable_tag，对应的分布table是table_tag _all，集群中有6个分片，sharding_key为intHash64(user_id).

通过设置参数distributed_product_mode='local'和distributed_group_by_no_merge=1使得returned 结果是 6 个单独分片的值而不是聚合值。

以下是两个测试。测试 1 得到正确的结果（count_1 的 6 条记录），但测试 2 是聚合的（只有 2 条记录）。如何让测试 2 return 成为 6 个分片的结果？


    create table database.table_tag on cluster c1
    (
    user_id  String,
    tag1     String,
    dt
    )
    order by user_id
    partition by dt
    setting index_granularity=128;
    
    /* test 1: */
    select
    sum(case when tag1='1' then 1 else 0 end ) as count_1
    from database.table_tag_all
    where dt in ('202102','202101')
    SETTINGS distributed_group_by_no_merge=1;
    
    
    /* test 2: */
    select count_1,count(1) 
    from (
    select
    user_id,
    sum(case when tag1='1' then 1 else 0 end ) as count_1
    from database.table_tag_all
    where dt in ('202102','202101')
    group by user_id
    SETTINGS distributed_group_by_no_merge=1;
    ) t1
    group by count_1
    SETTINGS distributed_group_by_no_merge=1;
    
    /*
    count_1  count()
    0        1222122
    1        33821
    */

Answer 1

试试这个查询：

SELECT
    shard_number,
    count_1,
    count()
FROM
(
    SELECT
        any(_shard_num) AS shard_number,
        countIf(tag1 = '1') AS count_1
    FROM database.table_tag_all
    WHERE dt in ('202102','202101')
    GROUP BY user_id
)
GROUP BY
    shard_number,
    count_1
SETTINGS distributed_group_by_no_merge = 1

期望分布table到return每个分片的结果，而不是聚合值

Expect the distributed table to return the results of each shard, not the aggregated value

clickhouse