Custom column - Select date from one column, or other date columns if null

[DataScope06]

My dataset has 3 different column dates: ORDER_DATETIME, ACTUAL_SHIPMENT_DATE, PROMISE DATE. I have a preferred hierarchy for selecting dates for a custom date column. If one of the date fields is null, then the next date field in the hierarchy should be used.

I have the SQL code but don't know the proper dax function. SQL is below

 CASE WHEN

ACTUAL_SHIPMENT_DATE is null then PROMISE_DATE
              WHEN PROMISE_DATE is null then ORDER_DATETIME
              else ACTUAL_SHIPMENT_DATE

END

The table looks like this

ACTUAL_SHIPMENT_DATE	PROMISE_DATE	ORDER_DATETIME
1/1/2020	1/2/2020	12/31/2019
	3/1/2020
	2/1/2021	2/2/2021
		4/1/2021

I would like a date column that shows this:

Date

1/1/2020

3/1/2020

2/1/2021

4/1/2021

[vojtechsima · Accepted solution]

Hello, @DataScope06,
this should work:

Date = 
var ActualShipment = 'Table'[ACTUAL_SHIPMENT_DATE]
var Promise = 'Table'[PROMISE_DATE]
var Order_ = 'Table'[ORDER_DATETIME]

var check = 
SWITCH(TRUE(),
    ISBLANK(ActualShipment), IF(ISBLANK(Promise), Order_, Promise),
    ActualShipment
 )

return check

[DataScope06]

I think your answer works, I will mark that as the solution, @vojtechsima.

Before you submitted the solution I did figure out how to make a custom column in Power BI, then I used this formula (copied from power query):

if [ACTUAL_SHIPMENT_DATE] != null then [ACTUAL_SHIPMENT_DATE]

else if [ACTUAL_SHIPMENT_DATE] = null then [PROMISE_DATE]

else if [PROMISE_DATE] = null then [ORDER_DATETIME]

else [ACTUAL_SHIPMENT_DATE]