I am trying to run a simple sql query but must be doing something wrong. Basically there are two tables, one containing category information and another containing categories that should be blocked. I want to make a sql query that grabs all of the categories except those listed in the blocked list. Below is the sql string I used, instead of just the unblocked categories being returned it returns the rows of the unblocked categories and then another copy of all categories.

SQL String I am using:
"SELECT categories.catID, categories.catName FROM categories, blockedcategories WHERE categories.catID != blockedcategories.catID"

Data in categories table

catID | catName
----------------------
1 | Test Category
----------------------
2 | Test Category2
----------------------
3 | Test Category3
----------------------
4 | Test Category4


Data in blockedcategories table

catID
----------
1
----------
3


Data returned when I run my sql string


catID | catName
----------------------
2 | Test Category2
----------------------
4 | Test Category4
----------------------
1 | Test Category
----------------------
2 | Test Category2
----------------------
3 | Test Category3
----------------------
4 | Test Category4


Desired results if SQL string worked correctly

catID | catName
----------------------
2 | Test Category2
----------------------
4 | Test Category4

try:

SELECT DISTINCT categories.catID, categories.catName FROM categories WHERE categories.catID <> ALL (SELECT catId FROM blockedcategories);

or maybe with WHERE NOT EXIST

hope this helps, I'm tired

Hi, Please try it..

select categories.catID, categories.catName
from categories where categories.catID not in(
select blockedcategories.catID from blockedcategories)