To execute a query on database, first connect to corresponding database then select it on Connections list and click on Query tool icon:
After click a new panel opens on the right – upper panel is for query entering and lower displays data output and messages.
Entery query and press F5 to see data output:
If query is invalid a message appears. Correct query and run it again. It is possible that some actions are not supported by SQL browser then you need to use SQL server tools such as pgAdmin and SQL Studio Manager.
You can open more Query tabs by clicking on Query Tool icon.