Allows you to manipulate the WP database by inserting, deleting, selecting, etc.
Whenever you need data from the database that could not reasonably be obtained through WP Queries, or perhaps if you have an advanced idea for which you need the database.
Action from the dropdown list.
Select and Query both give you a custom field into which to enter a query. What's the difference?Select uses get_results(), while Query uses the generic query() method.Insert, Update, Delete, or Replace, you will need to fill out key -> value pairs that correspond to the columns in the table you're modifying.
last_result. This is the result from the last query you've run. Make sure to store it with e.g. Set Parameter Element if you wish to keep it later on, because subsequent queries will overwrite this result.
insert_id that is automatically generated when you insert. As stated before, if you need this data, make sure to store it so it doesn't get overwritten.