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What is a Filter in tableau?
Filter in general means to select or remove a particular type of information from something. Here in tableau, filtering data is a necessary part of analyzing and showing the data as needed. Let’s learn about the types of filters used in Tableau.
We have different filters which helps us filtering the data in different levels. It is very important to understand the order and how each filter works. Using a wrong filter in a wrong place gives a different and inaccurate outcome.
Let’s learn a little bit about each filter.
Extract Filter :
Extract filter is used only when the user extracts the data from the data source. It means the extract connection will extract the data from data source and creates a local copy in Tableau repository. Hence reducing the number of times Tableau queries the data source.
To add the extract filter, click the ‘Edit’ option once the connection has been changed to Extract.
By clicking it we get the option to add the filters using the ‘Add’ option. Once selected, there will be multiple options available to filter like General (select from list, custom value list and use all) WildCard, Condition and Top filters which can be used as needed.
Data Source Filter :
A data source filter is used to filter the data in the data source level. It can restrict the records present in the data set. In simple words, it reduces the amount of data being fed into Tableau. It can be used to control the sensitive data.
Data source filter works on both live and extract connection. This filter is similar to extract filter on securing the data. Since the data source filter and extract filter is not linked to each other, if the connection is changed back from extract to a live connection the Data Source Filters will still be intact.
The data source filter can be added using the ‘Add’ option in the data source tab.
Context Filter :
One of the most important filters in the worksheet level is the Context filter. It is an independent and the top in the chain filter as it can create a separate dataset out of the original data set and compute the selections made in the worksheet. Context filter is used to improve the performance of the dashboard.
For example, if we have an important filter that needs to be performed before the other filters. Making it a context filter will make it proceed first and the other filters will be performed next. So the filters applied to a worksheet will be performed on the data that has been filtered based on the context filter.
To add the context filter, drag and drop the dimension to the filters card. Right click the dimension and click ‘Add to Context’. Once the context filter is added the blue pill changes to grey.
The context filter can be removed the same way it was added. Right click the dimension and click ‘Remove from context’.
Dimension Filters :
When dimensions, groups, bins and sets are used in the filter it is called as Dimension filter. Another name for dimension filter is ‘Non-Aggregated Filter’.
Once a dimension is dragged and dropped in the filter card a pop-up appears from which the filter can be set from the list, Wildcard match, top and bottom conditions.
Since the dimensions has discrete categorical data, filtering this type of field generally involves selecting the values to include or exclude.
Measure Filter :
Measure filters can filter the data based on measures like a set or range of values. Measure filters is also called as Aggregated filters since the aggregation functions are involved in the filter.
Aggregated filters are applied after Non-Aggregated filters, meaning the Measure filters are always applied after the Dimension filters.
When a Measure is dragged and dropped in the filter card it gives the option to choose from the list of aggregation.
Once the aggregation is selected it gives the options to set the filter to a Range of values (minimum and maximum range of values can be defined), At least (minimum measure value can be defined), At most (maximum measure value can be defined) and Special (option to select null or non-null values) to filter the data as needed.
Likewise when a date is added to the filter, we get a set of date relevant filtering options like Range of dates, Years, Quarters, Months, Days and more to apply the filter accordingly.
Table Calculation Filter :
When a table calculation is applied to the worksheet, applying a filter there can be tricky. We use Table calculation filters in such situations. Here, Tableau takes account of any table calculations in the view first, and then applies table calculation filters on the results in the current view.
Filters based on table calculations do not filter out underlying data in the data set, because table calculation filters are applied last in the order of operations.
For example when we have totals in the view, add and right click the table calculation in the filter card and click ‘Apply to Totals’ to apply the table calculation filter to all of the results in the table, including the totals.
These are a few scoops about the Order of operations in Tableau filters. There is still a lot to learn about the filters like User filters, implementing filters, filter card modes, how filter appears in the worksheet and dashboards and much more which hopefully I will write soon. Till that Happy learning! Reference : https://help.tableau.com/current/pro/desktop/en-us/filtering.htm, https://www.javatpoint.com/tableau, https://www.guru99.com/filter-data-tableau.html