Is there a way to emulate the functionality of this without a subquery:
SELECT a, b, c FROM tblFOO WHERE tblFOO.id NOT IN ( SELECT id FROM tblBAR)
If the operator was IN instead of NOT IN, the solution could easily be done with a SELECT DISTINCT and a JOIN. But, the NOT IN seems to be a completely different animal.
The way to do this is to use an outer join. When matching rows in an outer join, the database will assign NULLs to all the columns from the table which did not have a matching row.
For example, consider
tblFOO tblBAR id a b c id d e 1 A B C 1 D E 2 P Q R 3 X Y Z 3 J K 4 L M N 4 S T 5 W X Y
When doing a left outer join of these tables on the id column, the database will insert NULL into all tblBAR columns for any rows of tblFOO which don't have a match -- including the id column. In the above example, this would be for the rows in the result set where tblFOO.id is 2 and 5. So the SQL you want that is equivalent to the NOT IN syntax is
SELECT tblFOO.a, tblFOO.b, tblFOO.c FROM tblFOO LEFT OUTER JOIN tblBAR ON tblFOO.id = tblBAR.id WHERE tblBAR.id IS NULL
Notice that you are only SELECTing columns from tblFOO, while testing the id from tblBAR in the WHERE clause.
For More Information
- What do you think about this answer? E-mail the edtiors at editor@searchDatabase.com with your feedback.
- The Best SQL Web Links: tips, tutorials, scripts, and more.
- Have an SQL tip to offer your fellow DBAs and developers? The best tips submitted will receive a cool prize. Submit your tip today!
- Ask your technical SQL questions -- or help out your peers by answering them -- in our live discussion forums.
- Ask the Experts yourself: Our SQL, database design, Oracle, SQL Server, DB2, metadata, object-oriented and data warehousing gurus are waiting to answer your toughest questions.
Dig deeper on Oracle and SQL
Have a question for an expert?
Please add a title for your question
Get answers from a TechTarget expert on whatever's puzzling you.