Select 基于列的唯一记录，通过有条件地删除基于 sql 中的某些其他列值的具有相同列值的其他记录

Question

I am developing an Android app in which I am using the Room persistence library. In one of the Tables (Room Entity), I have a case where I want to select unique Records based on a column by conditionally removing the other record having the same column value based on some other column.

Consider the following table as a base.

S_ID	STATUS
1	Pending
1	Rejected
3	Approved
4	Approved
5	Pending
6	Rejected
7	Rejected

the expected result of the SQL query where I want a record with ' Rejected' status to be removed from results if its S_ID collides with another 'Pending' status record

S_ID	STATUS
1	Pending
3	Approved
4	Approved
5	Pending
6	Rejected
7	Rejected

what I have tried so far:

select DISTINCT s_id OR s_id = 0, * from TABLE1

Answer 1

I think You can try below query:

SELECT * FROM table1 WHERE table1.S_ID in (SELECT S_ID FROM table1 GROUP BY S_ID HAVING COUNT(S_ID)>0) and table1.[status]<>'Rejected'

Edited:

SELECT table1.S_ID, 
(select Alias.[Status] from Table1 Alias where Alias.S_ID=table1.S_ID  
and ((COUNT(table1.S_ID)>1 and Alias.[Status]<>'Rejected') or COUNT(table1.S_ID)=1) 
) as [Status]
FROM table1 GROUP BY S_ID HAVING COUNT(S_ID)>0

Answer 2

You can use aggregation for this:

select s_id, min(status) as status
from table_id
group by s_id;

This uses the fact that alphabetical ordering is used for max() and 'Pending' < 'Rejecdted' .