ORACLE Not In on Multiple Columns - sql

Question

Kindly have a look at the following structure.
Table: A
+---------+----------+
| Col1A | Col2A |
+---------+----------+
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 1 | 2 |
| 2 | 2 |
+---------+----------+
Table: B
+---------+----------+
| Col1B | Col2B |
+---------+----------+
| 2 | 1 |
| 3 | 1 |
+---------+----------+
Here is what I am trying to achieve that is to get the result as following:
Result
+---------+----------+
| Col1A | Col2A |
+---------+----------+
| 1 | 1 |
| 4 | 1 |
| 1 | 2 |
| 2 | 2 |
+---------+----------+
What I want :
I want to get the result of table A records which are not exists in Table B. It should be on the basis of both column. If the combination exist in first table then don't no show it.
What I have tried so far :
The first approach that I have tried was to use Not In statement. Following is my statement.
SELECT A.COL1A, A.COL2A
FROM A
WHERE A.COL1A NOT IN (
SELECT B.COL1B FROM B
);
But the issue with this approach didn't consider the second column. It will give me the following result.
+---------+----------+
| 1 | 1 |
| 4 | 1 |
+---------+----------+
While it will not show following as it should be sub-traced because of we didn't checked for other column.
+---------+----------+
| 1 | 2 |
| 2 | 2 |
+---------+----------+
Then I tried Not Exists but I didn't worked too. Here is my query.
SELECT A.COL1A, A.COL2A
FROM A
WHERE NOT EXISTS(
SELECT B.COL1B,B.COL2B FROM B
);
Edit
Sorry I forget to include the fiddle link.
Here it is : Fiddle Demo

Answer 1

For using Exists I think you should use it like this:
SELECT *
FROM A
WHERE
NOT EXISTS(SELECT 1
FROM B
WHERE A.Col1A = B.Col1B AND A.Col2A = B.Col2B)

Answer 2

One way to do this which is conceptually simple is to JOIN tables A and B on the two columns, and then SELECT only those rows in A which do not exist in B:
SELECT *
FROM A
LEFT OUTER JOIN B
ON (A.COL1A = B.COL1B AND A.COL2A = B.COL2B)
WHERE B.COL1B IS NULL

Answer 3

SELECT *
FROM a
WHERE (col1a, col2a) NOT IN (SELECT col1b, col2b FROM b);
But be aware that this will fail if either col1b or col2b contains NULL values.
SQLFiddle DEMO

Answer 4

SELECT A.COL1A, A.COL2A
FROM A
WHERE (Col1A, Col2A) NOT IN (
SELECT Col1B, Col2B FROM B
);
You can even use:
SELECT A.COL1A, A.COL2A
FROM A
WHERE (Col1A, Col2A) NOT IN (
(2, 1),
(3, 1)
);