如何对整数列执行 group_concat？

Question

此查询显示过去 2 周内一系列天数中 3 个端点的综合性能（使用某些优先级决定）。

select
    date,
    GROUP_CONCAT(endpoint, ', ') as endpoints, -- This works fine, since endpoint is string
    GROUP_CONCAT(success, ', ') as endpoints_successes, -- This fails
    (sum(success) / sum(attempts) * 100) as percentage
from
    some_table
where 
    and datadate = from_timestamp(date_sub(now(), 14), 'yyyyMMdd')
    and endpoint in ( 
        select distinct endpoint 
        from some_table
        order by some_priority desc 
        limit 2
    )
group by date
order by date

为了在仪表板中显示，我需要使用 group_concat 之类的方法组合数据集的值。这似乎适用于 String 类型的列。

然而，当我想合并 success 字段的值进行显示时，它失败并出现以下错误：

No matching function with signature: group_concat(BIGINT, STRING)

我应该如何将 Int 转换为 String 以便在 group_concat 中使用，或者是否有另一种完全相同的方法？

Answer 1

先尝试将这些数值转换为 STRING，然后再使用 GROUP_CONCAT:

汇总它们

SELECT
    date,
    GROUP_CONCAT(endpoint, ', ') AS endpoints,
    GROUP_CONCAT(CAST(success AS STRING), ', ') AS endpoints_successes,  -- cast here
    SUM(success) / SUM(attempts) * 100 AS percentage
FROM some_table
WHERE
    datadate = FROM_TIMESTAMP(DATE_SUB(NOW(), 14), 'yyyyMMdd') AND
    endpoint IN (SELECT endpoint FROM some_table ORDER BY some_priority DESC LIMIT 2)
GROUP BY date
ORDER BY date;

如何对整数列执行 group_concat？

How to do group_concat with Integer columns?

sql

impala