DAX uses BLANK to mean no value at all. It resembles NULL in SQL but behaves more like an empty cell in Excel, so adding 20 to it returns 20; the BLANK function creates one and ISBLANK detects it.
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In the Ultra Transcenders books
Each book explains BLANK in context, with comparison tables and the common traps.
Terms in this definition
- DAX
Short for Data Analysis Expressions, the formula language you write measures, calculated columns and row-level security rules in, within tabular semantic models in Power BI, Excel Power Pivot or Analysis Services.
- ALL
A DAX function that ignores any filters and gives back every row of a table or every value of the named columns. Used within CALCULATE, it works as a modifier that clears filters, although REMOVEFILTERS states that intent more clearly where it is available.
- NULL
Marks that a row has nothing in a particular column, as when a person has no middle name. Columns defined NOT NULL can never be left empty.
- Serverless
Compute tier for single Azure SQL databases that scales automatically, pauses when idle and charges by the second. It is offered in General Purpose and Hyperscale, not Business Critical, and reserved capacity does not apply.
- LIKE
Compares strings with a pattern that can contain the % and _ wildcards. Because it only understands character patterns, searching big volumes of text this way is much slower than using full-text search.
- ISBLANK
Returns TRUE in DAX if a value is BLANK, which is roughly what NULL means in SQL.
Related terms
- AVERAGE
A DAX function giving the mean of a single numeric column; blank cells are skipped while zeros are included. To average a calculation worked out for each row, AVERAGEX is used instead.
- AVERAGEX
Returns the mean of an expression after computing it once for each row in a table; if the table has no rows, this DAX iterator gives BLANK.
- Blank row
When fact rows carry a key that doesn't exist in the related one-side table, a regular relationship gathers them under an added virtual row, so referential integrity problems surface as (Blank). Limited relationships don't do this.
- COUNTA
Returns how many cells in a column are not blank, whatever the data type, so Boolean columns are handled too.
- COUNTAX
A DAX iterator that evaluates an expression across a table's rows and counts how many results are not blank, logical values included.
- COUNTBLANK
A DAX function giving the number of empty cells in a column. Zero values do not count as blank, and if the column has no rows at all the result is BLANK rather than zero.
- CUSTOMDATA
Reads whatever an embedding application (or anything else) put in the connection string's CustomData property, and returns blank when that property is empty. This is a DAX function.
- DATESBETWEEN
A DAX function that returns all dates between a given start and end date. Leaving the start as BLANK makes it begin at the earliest date in the column, producing life-to-date figures.