Description
The Database join step allows you to run a query against a database using data from previous steps. The parameters for this query can be specified as follows:
- as question marks (?) in the SQL query.
- as fields in the data grid.
The two must be in the same order (the two what must be in the same order?). For example, Database join allows you to run queries looking up the oldest person who bought a specific product as shown below:
SELECT customernr FROM product_orders, customer WHERE orders.customernr = customer.customernr AND orders.productnr = ? ORDER BY customer.date_of_birth
You then need to specify the productnr as a parameter and you will get the customernr included in the result.
Options
The following table desribes the options for the Database Join step:
Option |
Description |
---|---|
Step name |
Name of the step; This name has to be unique in a single transformation |
Connection |
The database connection to use |
SQL |
SQL query to launch towards the database; use question marks as parameter placeholders |
Number of rows to return |
Zero (0) returns all rows; any other number limits the number of rows |
Outer join? |
Enable to always return a result, even if the query did not return a result |
Parameters table |
Specify the fieldns containing parameters and the parameter type |