In order to use our SQL query tool, you must first navigate to the "Map Viewer" mode by clicking on "View" in the top right corner of your web map. Once there, click on the menu icon (hamburgeler) to the right of the layer, and choose view attributes. At the top right of the attribute table is a magnifying glass, which if you click on it, brings up a window to use the SQL wizard or manual SQL search option. SQL searches allow the users to apply a number of different conditions to the search, therefore allowing for more advanced data management. We also recently added an option to expand the attribute table, which you can do by clicking on the full extent icon at the bottom left of the table. 

Update: New Filter List option added to SQL search tool, which when enabled will mean that the results of your query are all that will show in the attribute table. When turned off, the entire attribute will still show but your search results will be highlighted.