The FILTER function is used to filter a table based on certain condition(s) and is somewhat similar to Filtering Data in MS- Excel. Let’s explore the intricacies of the DAX FILTER function.   DAX Filter Function Video Take a look at this video to get a better hold of the topic.   DAX FILTER Function Syntax This function accepts two arguments Table Condition The first argument, i.e., Table, accepts a physical or a virtual table to Filter.  A physical table can be seen in the data model. A virtual table is the one created on the fly. The second argument, i.e. Condition accepts a logical test that is performed in each row of the table. All rows that satisfy the condition, i.e. return TRUE are kept while other rows are removed. Keep in mind the condition must return a True or False output else it stands invalid.   Important – The output of the FILTER function is a table containing the rows that satisfied the condition.    DAX FILTER Function in Action Let’s run the FILTER Function on this data model with Sales and a standard Calendar Table linked with a one to many relationship.   Because the FILTER Function returns a Table, let’s create a Table.  Go to Table Tools >> New Table. Let’s create a simple table with a condition on the Sales Amount column >= $20. Consider the following DAX Code. Dummy Table = FILTER (     Sales, — This is the Table     Sales[SalesAmount] >= 20 — A condition for each row, returns TRUE / FALSE output )   Input 1 Table – The Sales table is filtered Input 2 Condition – Check if each row is >= $20. Note the condition will return either a TRUE or FALSE for each row of the Sales Table. Output Table – You’ll get a table with rows that matched the condition.   FILTER Function used on a Virtual Table Sales was a physical table present in the Data Model, let’s see if we can apply the FILTER function to a table that doesn’t physically exist i.e. a Virtual Table. Let’s solve this Question – Get a table of dates where the sales amount is >=  $50000. Consider this DAX for creating a Table. Dummy Table 2 = FILTER ( VALUES ( Sales[OrderDate] ), — VALUES creates a single columnar table with unique dates.   [Total Sales] >= 50000 — For each date (row) check if Total Sales >= 50000 )   Input 1 Table – The VALUES Function creates a one columnar table with unique Dates. Input 2 Condition – Check if Total Sales Value for each date is >= $50,000. Again, the condition will return either a TRUE or FALSE for each row of the Virtual Table. Output Table – You’ll again get a table with rows that matched the condition. The output contains 133 rows, i.e. there were 133 days when the sales were more than $50,000.   FILTER Function used in a Measure Question – Find the Total Sales Amount for High Selling Days. A High Selling Day will have Sales >= $50,000. Let’s build on this from the previous example. Consider a new measure with the same DAX Code used earlier for creating a virtual table. Sales >50k= FILTER (     VALUES ( Sales[OrderDate] ), — The VALUES function creates a Virtual Table.     [Total Sales] >= 50000 — This condition is tested for each row of the Virtual Table ) The Problem – If you drag this measure to a visual / a Pivot Table, this will throw an error. The Reason – Since the FILTER Function delivers a table, a table cannot be summarized as a single value / scalar output. The Solution – We need to SUM the values of the table to get this right. Consider the revised DAX Measure. Sales >50K = CALCULATE (     [Total Sales],     FILTER (         VALUES ( ‘Calendar'[Date] ),         [Total Sales] >= 50000     ) ) The CALCULATE function outside aggregates (sums) the sales value for the rows returned by the FILTER Function. The output obtained would be as follows   DAX FILTER Function – A Quick Summary FILTER function has two parts, a table and a condition. The Table can be Physical or Virtual. The condition must be return a TRUE / FALSE. The condition is checked for each row of the table and the row with TRUE output are kept. The output of the function is a table. If you are using the FILTER function in a measure, you need to aggregate the table to return a scalar value.     More on DAX Functions The EARLIER Function The CALCULATE Function The ALLSELECTED Function A few tricks with the FORMAT Function Check out my DAX Function Playlist