Question

我的SQL Server数据库中有以下表格：

| ID   | Class                                             | CId   | PId 
| 7865 | Add Class for Prop                                | 1043  | 1 
|   82 | Advanced Carpet Spotting Advanced Carpet Spotting | 1043  | 1 
|   82 | Advanced Carpet Spotting Advanced Carpet Spotting | 1042  | 1 
| 7863 | aTesting                                          | 1042  | 0 
| 7218 | aUnique                                           | 1042  | 0 
|   85 | Body Mechanics                                    | 1042  | 1 
|   88 | Carpet Bonnet Cleaning                            | 1044  | 0 
|   89 | Carpet Shampooing/Extraction                      | 1044  | 1 
| 7829 | Class 10                                          | 1044  | 0

我有多个CId和PId

如果不同的CId有相应的PId = 1那么，

Set CId = 1 Otherwise 0

我想要这样的输出

|  CId | Status | Count  
| 1042 |   0    |   4 
| 1043 |   1    |   2 
| 1044 |   0    |   3

我可以通过使用多个查询获得所需的输出，但我想要更优化的一个。

请提出解决方案。谢谢。

Answer 1

select cid, 
       case when count(case when pid = 1 then 1 end) > 0 
            then 1 
            else 0 
       end as status, 
       count(*) as count
from your_table
group by cid

Answer 2

如果PId始终为1和0，您可以执行以下操作。

SELECT
    CID,
    AVG([Status] * 1) AS [Status],
    COUNT(*) AS [Count]
FROM
    YourTable
GROUP BY 
    CID

Answer 3

使用CASE表达式检查PId的总和是否等于PId的数量。

<强>查询

select [CId], 
case when sum([Cid]) = count([CId]) then 1 
else 0 end as [Status],
count([CId]) as [Count]
from [your_table_name]
group by [CId];

同样PId应该只有1和0值。

SQL Server数据库的优化查询

3 个答案: