The Apply SQL Transformation module lets you run a SQL query on the input dataset(s) and get the desired result. You can find it under Data Transformation | Manipulation in the module palette. The module can take one, two, or three datasets as inputs. The dataset coming from input 1 can be referenced as t1. Similarly, you can refer to datasets from input 2 and input 3 as t2 and t3, respectively. On the properties of the module, the Apply SQL Transformation module takes only a parameter as a SQL query. The syntax of the SQL it supports is based on the SQLite standard.

In the following illustration, the module takes data from two datasets, joins them, and selects fewer columns. It also generates calculated columns by applying an aggregation function, AVG.

If you are already familiar with SQL, you may find this module very handy for data transformation.