There are two types of SOQL queries: simple query and relationship query.

Simple query retrieves data from only one object. For more information about how to set the
module and schema for generating simple queries, see How to set schema for generating the simple query.

Relationship query retrieves data from more than a single type of object, including
child-to-parent and parent-to-child relationship queries.

For more information about how to set the module and schema for generating child-to-parent
relationship queries, see How to set schema for generating the child-to-parent relationship query.

For more information about how to set the module and schema for generating parent-to-child
relationship queries, see How to set schema for generating the parent-to-child relationship query.

Note that before setting the module name and schema columns for generating the relationship
query in the Basic settings view of
tSalesforceInput, you need to first identify the relationship type
(child-to-parent or parent-to-child) of the query to be generated, because the methods of
setting the schema column names for these two kinds of relationship queries are somewhat
different. The main difference between the child-to-parent and parent-to-child relationship
queries is that the parent-to-child relationship query is specified by using the subquery
enclosed in parentheses, while the child-to-parent relationship query is not. For more
information about the relationship queries in SOQL and how to identify the relationship
queries, see Relationship Queries.