Question

I have 5000 records, two fields of which contain Categories and SubCategories. There are only a (small) finite number of possible values. These are kept in tblCategory, tblSubCategory, they are not linked (and do not need to be). Note that the Categories/SubCategories in the main table do change frequently.

I want to add a flag in my view that checks if the categories/subcategories in each record are valid by checking the contents of the table. The Categories/SubCategory tables will rarely change.

I just want something similar to CASE WHEN tblRecords.Category is in tblCategory.Category THEN 0 ELSE 1 END AS errCategory

How can I achieve this?

Answer 1

Try this:

CASE WHEN (SELECT COUNT(Category) 
        FROM tblCategory WHERE 
       tblCategory.Category = tblRecords.Category) > 0 
THEN 0 ELSE 1 END AS errCategory