需要幫助的加入問題

Question

我有2個表

 

Table 1 

ID Status 
1 D 
2 F 
3 D 


Table 2 

SID ID Approve 
1 1 N 
2 1 Y 
3 1 Y 
4 2 Y 
5 3 Y 

Result:- Should be 
Table 1 (ID, Status) 
3, D 
2,F 

如果不顯示1（作爲子行的一個有N個在批准列）

我需要一個查詢來加入對ID 2個表並查找在批准列中沒有N的記錄。有沒有人有任何線索如何實現這一點？

我試圖

 
SELECT * FROM Table1 AS t1 
INNER JOIN Table2 AS t2 
ON t2.id = t1.id 
WHERE t2.Approve != 'N' 

不工作

Answer 1

更有效，可能更容易閱讀如下：如果一個項目沒有批准或不批准

SELECT * FROM Table1 AS t1 
LEFT JOIN Table2 AS t2 
ON t2.id = t1.id 
group by t1.id HAVING sum(t2.approve='Y') = count(t1.id) 

Answer 2

SELECT * 
FROM Table1 t1 
WHERE NOT EXISTS(SELECT * FROM Table2 t2 WHERE t2.ID = t1.ID AND t2.Approve = 'N') 

Answer 3

請嘗試

SELECT distinct t1.* 
FROM Table1 AS t1 
INNER JOIN Table2 AS tyes 
ON tyes.id = t1.id 
AND tyes.approve ='Y' 
LEFT OUTER JOIN Table2 as tno 
ON tno.id = t1.id 
AND tno.approve ='N' 
where tno.sid is null 

它會選擇哪個是明確地認可，從不表現出的任何行

Answer 4

Select * from table1 where id not in (select id from table2 where approve = 'N') 

Answer 5

ID 1仍然被返回，因爲表2中還有一個記錄，其中批准='Y'代表ID 1. 如果您想排除任何SID爲「N」的任何ID，那麼您必須使用子查詢;大致爲：

SELECT t1.ID,T1.Status FROM Table1 AS t1 INNER JOIN Table2 AS t2 ON t2.id = t1.id 
where t1.id NOT IN (select id from Table2 where approve = 'N' and id = t1.id) 

問候，
斯泰恩