SAMEPERIODLASTYEAR DAX Function (Time Intelligence) Context Transition
Returns a set of dates in the current selection from the previous year.
Syntax
SAMEPERIODLASTYEAR ( <Dates> )
| Parameter | Attributes | Description |
|---|---|---|
| Dates |
The name of a column containing dates or a one column table containing dates. |
Return values
Table A table with a single column.
The corresponding dates in the previous year.
Notes
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.
Remarks
The dates argument can be any of the following:
- A reference to a date/time column. Only in this case a context transition applies because the <Dates> column reference is replaced by
- CALCULATETABLE ( DISTINCT ( <Dates> ) )
- A table expression that returns a single column of date/time values.
- A Boolean expression that defines a single-column table of date/time values.
The result table includes only dates that exist in the dates column.
Internally SAMEPERIODLASTYEAR corresponds to the following call of DATEADD:
DATEADD ( <Dates>, -1, YEAR )
Examples
-- SAMEPERIODLASTYEAR returns the selected period shifted back one year.
EVALUATE
VAR StartDate = DATE ( 2008, 07, 25 )
VAR EndDate = DATE ( 2008, 07, 31 )
RETURN
CALCULATETABLE (
SAMEPERIODLASTYEAR ( 'Date'[Date] ),
'Date'[Date] >= StartDate &&
'Date'[Date] <= EndDate
)
ORDER BY [Date]
| Date |
|---|
| 2007-07-25 |
| 2007-07-26 |
| 2007-07-27 |
| 2007-07-28 |
| 2007-07-29 |
| 2007-07-30 |
| 2007-07-31 |
-- DATEADD is a more generic functions.
-- It shifts a period back and forth over time using
-- DAY, MONTH, QUARTER, YEAR
-- This example produces the same result as SAMEPERIODLASTYEAR
EVALUATE
VAR StartDate = DATE ( 2008, 07, 25 )
VAR EndDate = DATE ( 2008, 07, 31 )
RETURN
CALCULATETABLE (
DATEADD ( 'Date'[Date], -1, YEAR ),
'Date'[Date] >= StartDate &&
'Date'[Date] <= EndDate
)
ORDER BY [Date]
| Date |
|---|
| 2007-07-25 |
| 2007-07-26 |
| 2007-07-27 |
| 2007-07-28 |
| 2007-07-29 |
| 2007-07-30 |
| 2007-07-31 |
-- All time intelligence functions are designed to return a table
-- to be easily used in CALCULATE as a filter.
EVALUATE
VAR StartDate = DATE ( 2008, 01, 01 )
VAR EndDate = DATE ( 2008, 01, 31 )
RETURN
{
CALCULATE (
CALCULATE (
[Sales Amount],
SAMEPERIODLASTYEAR ( 'Date'[Date] ) -- 2007-01-01 : 2007-01-31
),
'Date'[Date] >= StartDate &&
'Date'[Date] <= EndDate
)
}
| Value |
|---|
| 794,248.24 |
Related functions
Other related functions are:
Last update: Apr 2, 2021 » Contribute » Show contributors
Contributors: Alberto Ferrari, Marco Russo
Microsoft documentation: https://docs.microsoft.com/en-us/dax/sameperiodlastyear-function-dax
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