Question

我有一张桌子

id | event_id | stat_count | month | year
1  | 1        | 12         | 01    | 2070 
2  | 1        | 11         | 02    | 2070 
3  | 2        | 14         | 01    | 2070 
4  | 2        | 15         | 04    | 2070

等等。

我需要通过event_id分组来获取数据。月份将是从01到12，但不一定是所有月份，并且stat_count可能已插入表格中。提供的日期不是英文日期格式。我需要得到如下结果

event  data
Fevent 12,21,0,3,0,9,0,0,12,23,34,0 
Fevent2 12,0,3,4,3,0,3,2,3,4,0,0

等等。

更新

以下是我尝试使用group_concat的查询：

select 
    (select event_name from vital_events where id=VEC.vital_event_id) name,
        group_concat(

                        CASE    when VEC.month='01' then VEC.stat_count
                            when VEC.month='02' then VEC.stat_count
                            when VEC.month='03' then VEC.stat_count
                            when VEC.month='04' then VEC.stat_count
                            when VEC.month='05' then VEC.stat_count
                            when VEC.month='06' then VEC.stat_count
                            when VEC.month='07' then VEC.stat_count
                            when VEC.month='08' then VEC.stat_count
                            when VEC.month='09' then VEC.stat_count
                            when VEC.month='10' then VEC.stat_count
                            when VEC.month_nepali='11' then VEC.stat_count
                            when VEC.month='12' then VEC.stat_count
                          else 0 end order  by VEC.month
                        )as data 
        from vital_event_counts as VEC
group by VEC.vital_event_id

Answer 1

使用CROSS JOIN的另一个版本查找应包含的所有月份，然后对具有现有值的表使用LEFT JOIN;

SELECT x.event_id, 
       GROUP_CONCAT(COALESCE(stat_count,0) ORDER BY x.month) stat_count
FROM 
 (SELECT DISTINCT event_id, m.month FROM Table1 CROSS JOIN
  (SELECT  1 month UNION ALL SELECT  2 UNION ALL SELECT  3 UNION ALL  
   SELECT  4       UNION ALL SELECT  5 UNION ALL SELECT  6 UNION ALL 
   SELECT  7       UNION ALL SELECT  8 UNION ALL SELECT  9 UNION ALL
   SELECT 10       UNION ALL SELECT 11 UNION ALL SELECT 12) m
  ) x
LEFT JOIN Table1 
  ON table1.month = x.month AND table1.event_id = x.event_id
 AND year = 2070
GROUP BY x.event_id

An SQLfiddle to test with

Answer 2

不漂亮，但是......

SELECT
 event_id,
 CONCAT(
  (SELECT COALESCE(SUM(stat_count), 0) FROM tbl WHERE id = t.id AND month = 1), ',',
  (SELECT COALESCE(SUM(stat_count), 0) FROM tbl WHERE id = t.id AND month = 2), ',',
  (SELECT COALESCE(SUM(stat_count), 0) FROM tbl WHERE id = t.id AND month = 3), ',',
  ⋮
  (SELECT COALESCE(SUM(stat_count), 0) FROM tbl WHERE id = t.id AND month = 12)
 ) AS data
FROM
 tbl AS t

如何在mysql中为多个数据分组数据？

更新

2 个答案: