sql查询从审计表中获取数据，其中列匹配一个值，但不匹配另一个

Question

I have a table t_audit with 4 columns: name, address, updated (Y or N), and user_id (ID of the user who updates it).

I want to search the audit table, to get the names of customers updated by user_id 1, but not 2.

I tried this:

select ta.name 
from t_audit ta 
where (ta.updated = 'Y' and user_id = 1 ) 
    and not exists (ta.updated='Y' and user_id = 2)

But it does not work. How can I fix this?

Answer 1

for Oracle

select ta.name 
from t_audit ta 
where (ta.updated = 'Y' and user_id = 1 ) 
minus
select ta.name 
from t_audit ta 
where (ta.updated = 'Y' and user_id = 2 ) 

for others

select ta.name 
from t_audit ta 
where (ta.updated = 'Y' and user_id = 1 ) 
EXCEPT
select ta.name 
from t_audit ta 
where (ta.updated = 'Y' and user_id = 2 ) 

Answer 2

Your not-exists syntax is incorrect, the following is untested of course by should be close to what you are expecting

select ta.name 
from t_audit ta 
where ta.updated = 'Y' and ta.user_id = 1  
  and not exists (
    select * from t_audit ta2
    where ta2.name=ta.name and ta2.updated='Y' and ta2.user_id = 2
)