Question

我对数据库比较陌生。如果我有如下表格，请说：

PHeader AHeader IHeader

p1       a1      0

p1       a1      2

p1       a1      3

p1       a2      0

p1       a3      0

p1       a4      0

p1       a4      2

p1       a4      3

p2       a5      0

预期输出为：

PHeader BCount  TCount


p1          2    2

p2          0    1

BCount：对于给定的PHeader和AHeader值，如果IHeader值具有（0,2＆amp; 3）的所有值，则PHeader的BCount值增加1，因为对于p1，它具有a1＆amp; a4的所有vaues均为0,2＆amp; 3作为IHeader值p1的BCount为2

TCount：对于给定的给定PHeader和AHeader值，如果IHeader值仅为0而不是2或3，则给定PHeader的TCount增加1.因此，对于p1的TCount 给出为2。

请您给我写一下查询的提示？

Answer 1

您可以使用两个聚合来解决此问题。内部聚合在pheader，aheader级别。这会计算您感兴趣的值。

外部的逻辑将您描述的逻辑应用于这些摘要：

select pheader,
       sum(ih_0 > 0 and ih_2 > 0 and ih_3 > 0) as bcount,
       sum(ih_0 > 0 and (ih_2 = 0 or ih_3 = 0)) as tcount
from (select pheader, aheader,
             sum(iheader = 0) as ih_0,
             sum(iheader = 2) as ih_2,
             sum(iheader = 3) as ih_3
      from table t
      group by pheader, aheader 
     ) pa
group by pheader;

编辑：

问题是标记为MySQL。以下内容适用于两个数据库：

select pheader,
       sum(case when ih_0 > 0 and ih_2 > 0 and ih_3 > 0 then 1 else 0 end) as bcount,
       sum(case when ih_0 > 0 and (ih_2 = 0 or ih_3 = 0) then 1 else 0 end) as tcount
from (select pheader, aheader,
             sum(case when iheader = 0 then 1 else 0 end) as ih_0,
             sum(case when iheader = 2 then 1 else 0 end) as ih_2,
             sum(case when iheader = 3 then 1 else 0 end) as ih_3
      from table t
      group by pheader, aheader 
     ) pa
group by pheader;

Answer 2

请检查beloq sql查询

SELECT 
PHeader ,
COUNT(*) as BCount  , --total 
SUM(CASE WHEN PHeader = 'p1' THEN 1 ELSE 0 END) as TCount

这 yourtablename PHeader小组

希望这会给你一些想法。

根据同一列的多行值获取计数

2 个答案: