A data warehouse is comprised of many tables, and we rarely get an answer with one table alone. To get business answers, we need to join two or more tables. In upcoming recipes, we will see how to improve this joining and troubleshoot some of the issues that occur while joining tables.
We will answer the following questions in our recipes:
- What join types are supported in Teradata
- The difference between outer and inner joins
- Resolving product joins
- How to improve join performance
The following illustration gives a better understanding of the relationship:
There are two methods of writing joins; one is with Oracle syntax, and the other ANSI, which is the recommended one. The following is a query with Oracle syntax:
/*Query with Oracle Syntax*/
SELECT A.QTR_YEAR, A.WEEK_YEAR , B.INVOICE_NME
FROM Table_A.CUR A, Table_B.INVOICE_CNTY b ,
WHERE B.store_Id=A...
