SQL查詢來比較有統計記錄大於1

Question

我有一個包含ID的表格，並回答它看起來像列：

| id | answer | 
| 1 | Yes | 
| 2 | No | 
| 3 | Unsure | 
| 1 | No | 
| 1 | Unsure | 
| 3 | Yes | 
| 2 | Unsure | 
| 4 | NULL | 
| 4 | Unsure | 
| 4 | No  | 

我想輸出的方式，如果用戶ID曾經回答「是「（例如id 1），那麼最終輸出應該有1. 但是，如果用戶標識已回答」否「和」NULL「，則輸出應爲」否「 此外，如果用戶標識回答」不確定「否「或」不確定「和」空「，則輸出應該是」不確定「

最終輸出：

| id | answer | 
| 1 | Yes | 
| 2 | Unsure | 
| 3 | Yes | 
| 4 | Unsure | 

Answer 1

你想用聚集和case邏輯是：

select id, 
     (case when sum(case when Answer = 'yes' then 1 else 0 end) > 0 
      then 'yes' 
      when sum(case when answer = 'unsure' then 1 else 0 end) > 0 
      then 'unsure' 
      else 'no' -- or perhaps max(answer) 
     end) as answer 
from t 
group by id; 

如果只可能是「是」，「否」，「不確定」和NULL，那麼你可以採取一個捷徑：

select id, 
     (case when max(Answer) = 'yes' 
      then 'yes' 
      when max(answer) = 'unsure' 
      then 'unsure' 
      else 'no' -- or perhaps max(answer) 
     end) as answer 
from t 
group by id; 

Answer 2

CASE WHEN (.Answer IS NULL OR .Answer = 'No') THEN 'NO' ELSE (.Answer) END AS 'FILTERED ANSWER' 

這可以幫助你嗎？