A filter is a tool for sorting out unwanted records from a collection and quickly displaying the records you want to find.
There are two ways to add a filter to your collection in a collection view:
(1) – Add a filter to a particular column (i.e. collection field) displayed in your collection by hovering over a field's name and clicking on the appeared "add filter" icon.
(2) – Add a filter to any collection field (even if it's not displayed as a column in your collection) by clicking the "Filter" button in the top bar.
Once you do that, you'll be able to specify the filter type, the comparison value.
(1) - Choose a field you'd like to use to filter your records. For instance, if you want to filter records by the values in the price field, you would choose Price from the dropdown list. – only for (2)
(2) - Select a filter type: contains/starts with/etc. Filter types may vary depending on a field's type.
(3) - Enter the comparison value.
(4) - Click "Filter" or "Exclude" depending on how you want the filter to apply. The "Filter" option will leave only those records that match your search criteria The "Exclude" option will hide records that match your criteria
When you apply a filter, you'll see its tag appear in the top bar of the screen (1). If you want to be able to access the filtered data quickly, you can create a segment by clicking the disk icon (2).
Read more about segments here:
To create a SQL Query filter, you would have to click the "Filter" button in the top right corner of a collection view or hover over a collection column and hit "Add filter, then click "Use SQL".
Once it's done, you'll be taken a new window where you can specify the name of this filter, make it visible/invisible, and run a SQL query to apply this filter.
For instance, here we run a query to return a list with ID numbers of all available vehicles at the moment.
selectvehicle.idfromrideleft joinvehicleonride.vehicle_id=vehicle.idwhereis_opened=Truegroup byvehicle.id
To delete a filter, hover over its tag in the top bar and click on the appeared X sign.