SQL查询 - 从表中选择不同的值

Question

I have a table in which i have multiple entries against a FK. I want to find out the value of FK which do not have certain entries eg
my table has following entries.

PK----------------FK-----------------Column entries

1----------------100-----------------ab1
2----------------100-----------------ab2
3----------------100-----------------ab4
4----------------200-----------------ab1
5----------------200-----------------ab2
6----------------200-----------------ab3
7----------------300-----------------ab1
8----------------300-----------------ab2
9----------------300-----------------ab3
10---------------300-----------------ab4

Now, from this table i want to filter all those FK which do not have ab3 or ab4 in them. Certainly, i expect distinct values ie in this case result would be FK= 100 and 200.
The query which i am using is

select distinct(FK) 
from table1 
where column_entries != 'ab3' 
   or column_entries != 'ab4';

Certainly, this query is not fetching the desired result.

Answer 1

try the following :-

select distinct fk_col from table1
minus
(select distinct fk_col from table1 where col_entry='ab3'
intersect
select distinct fk_col from table1 where col_entry='ab4')

This will show all those FKs which do not have 'ab3' and 'ab4'. ie 100 and 200 in your case

Answer 2

The below script may be the solution if I got your question in a right way.

SELECT DISTINCT(TableForeignKey)
FROM Test
WHERE TableForeignKey NOT IN (
SELECT T1.TableForeignKey
FROM Test T1 INNER JOIN Test T2 ON T1.TableForeignKey = T2.TableForeignKey
WHERE T1.TableEntry = 'ab3' AND T2.TableEntry = 'ab4')

SQLFiddle Demo

Answer 3

You could use GROUP BY with conditional aggregation in HAVING:

SELECT FK
FROM table1
GROUP BY FK
HAVING COUNT(CASE column_entries WHEN 'ab3' THEN 1 END) = 0
    OR COUNT(CASE column_entries WHEN 'ab4' THEN 1 END) = 0
;

The two conditional aggregates count 'ab3' and 'ab4' entries separately. If both end up with results greater than 0, then the corresponding FK has both 'ab3' and 'ab4' and is thus not returned. If at least one of the counts evaluates to 0, then FK is considered satisfying the requirements.