If Else Logic In Sql Select Query

Hi All

I have a sqlserver database with product, catagory and sub catagory format. Before I describe my problem, let me share whats I have in db. Their are two types of sinaros, either the products are directly assigned to a catagory or a product is placed in subcatagory that is in turn have a catagory. I use the following table struct for both of the scenarios:

Product>>subcat bridge>>subcatagory

Product>>catbridge>>catagory

Here are the queries to get them:

1. If product assinged direct in catagory then

select product.pid, product.Prd_heading,product.[Description], product.Brand, product.img from product,cat_bridge,category where product.id=cat_bridge.pid and cat_bridge.catid=category.catid;

2. If product assinged to sub cat then

select product.pid, product.Prd_heading,product.[Description], product.Brand, product.img from product,subcat_bridge,subcategory where product.pid=subcat_bridge.pid and subcat_bridge.subcatid=subcategory.subcatid and subcategory.catid=category.catid;

Now the problem is, I want to use a single query to download all the products to a CSV format and I need to combine both of the queries with a single one, probably with if else logic, but I am not getting it, I mean how to acheive. Can anyone help me sort this out?

 Thanks in Advance

Regards

Mykhan