Question

I have two tables with binding primary keys in the database and I want to find a disjoint set between them. For example,

Table1

ID	Name
1	John
2	Peter
3	Mary

Table2

ID	Address
1	address2
2	address2

So how do I create a SQL query so I can fetch the row with ID from table1 that is not in table2? In this case, (3, Mary) should be returned.

PS: The ID is the primary key for those two tables.

Answer 1

Try this

SELECT ID, Name 
FROM   Table1 
WHERE  ID NOT IN (SELECT ID FROM Table2)