user2961127 - 6 months ago 9

SQL Question

I have data table giving following results:

`number code`

1 A

1 B

1 A

2 B

2 A

3 A

4 B

How do i find distinct number from table having code as A. The number should only have code A in table and not have B in table.

For the above table: My answer would be 3. As it has only code A.

Answer

```
SELECT DISTINCT a.number
FROM TableName a
WHERE a.Code = 'A'
AND NOT EXISTS (Select 1
FROM TableName b
WHERE a.number = b.number
AND b.Code = 'B')
```