Queries are traditionnaly divided in the categories: DDL (Data Definition Language) ones and DML (Data Manipulation Language) ones.
Mergeant does not yet offer any way to create databases, tables, or any other objects in a database. This will be implemented in a future version.
With Mergeant, the only queries the user has to design are selection queries (SELECT statements using the SQL language), so the queries referenced in Mergeant are all about selection. Modification, insertion or deletion queries (other DML queries) are then made using the corresponding selection query.
The benefits are when the user wants to update results (or recordsets) of queries where there are some joins, where statements, etc: Mergeant will provide the user with a nice interface to help make some modifications to a defined table (in case the selection query is from several tables) where joins are presented as multiple choice lists.
As the user interface to build selection queries is limited (as *any* interface would be), there is still a possibility to manually enter queries which are sent to the DBMS (without checking anything!). However even if a hand made query is a selection query, it cannot be used to make modification queries (hopefully it will be in the future!).