Returns the first value in the column for which the expression has a non blank value.
The source values.
The expression to be evaluated for each value.
A table containing a single column and single row with the computed first value.
In order to use any time intelligence calculation, you need a well-formed date table. The Date table must satisfy the following requirements:
- All dates need to be present for the years required. The Date table must always start on January 1 and end on December 31, including all the days in this range. If the report only references fiscal years, then the date table must include all the dates from the first to the last day of a fiscal year. For example, if the fiscal year 2008 starts on July 1, 2007, then the Date table must include all the days from July 1, 2007 to June 30, 2008.
- There needs to be a column with a DateTime or Date data type containing unique values. This column is usually called Date. Even though the Date column is often used to define relationships with other tables, this is not required. Still, the Date column must contain unique values and should be referenced by the Mark as Date Table feature. In case the column also contains a time part, no time should be used – for example, the time should always be 12:00 am.
- The Date table must be marked as a date table in the model, in case the relationship between the Date table and any other table is not based on the Date.
The ColumnName argument can be any of the following:
- A reference to a column. Only in this case a context transition applies because the column reference is replaced by
- A table expression that returns a single column.
- A Boolean expression that defines a single-column.
The result table includes only values that exist in the ColumnName column.
Even though this function is commonly used for dates, it can be applied to a column of any data type.
The ColumnName argument must be a column. In certain conditions the function does not return an error passing a table with more than one column as ColumnName argument, but the behavior in that case is not supported and the error condition is not reported because it could break existing reports.
Learn more about FIRSTNONBLANK in the following articles:
Alternative use of FIRSTNONBLANK and LASTNONBLANK
You might have used FIRSTNONBLANK and LASTNONBLANK in semi-additive measures, but you might not be aware that their use is not limited to time intelligence functions. This article shows alternative scenarios where these functions are useful. » Read more
Semi-Additive Measures in DAX
Values such as inventory and balance account, usually calculated from a snapshot table, require the use of semi-additive measures. In Multidimensional you have specific aggregation types, like LastChild and LastNonEmpty. In PowerPivot and Tabular you use DAX, which is flexible enough to implement any calculation, as described in this article. » Read more
Optimizing LASTNONBLANK and LASTNONBLANKVALUE calculations
This article explains the behavior of LASTNONBLANK, LASTNONBLANKVALUE, and similar DAX functions, also providing patterns for performance optimization. » Read more
Other related functions are:
Contributors: Alberto Ferrari, Marco Russo
MSDN documentation: https://docs.microsoft.com/en-us/dax/firstnonblank-function-dax