SQL to DAX

[SuzieKidd]

How do I write the following SQL in DAX please

DATEADD(s,-1,DATEADD(mm,0,DATEADD(mm,DATEDIFF(mm,0,GETDATE()),0)))

Thank you

[smpa01 · Accepted solution]

@SuzieKidd 

select DATEADD(s,-1,DATEADD(mm,0,DATEADD(mm,DATEDIFF(mm,0,DATEFROMPARTS(2023,8,15)),0)))

returns

2023-07-31 23:59:59.000

You need DAX like this

Column = 
VAR dt = DATE(2023,8,15)
VAR yr = YEAR(dt)
VAR mo = MONTH(dt)
VAR date2 = DATE(yr,mo,1)
RETURN (date2-1)+0.99999

or 

Column = 
VAR dt = DATE(2023,8,15)
VAR yr = YEAR(dt)
VAR mo = MONTH(dt)
VAR date2 = DATE(yr,mo,1)
RETURN (date2-1)+CONVERT(TIME(23,59,59),DOUBLE)

replace GETTODAY() with TODAY() in DAX

Why 0.99999 works here I have no idea,

@AlexisOlson  do you know why it works? Can we achieve that part through a calculation rather than hardcoding

[AlexisOlson]

@smpa01 You're subtracting a day and then adding back almost a whole day.

(1-0.99999) days = 0.000001 days = 0.864 seconds.

So, essentially, you're taking midnight on the first of the month and subtracting roughly one second.

Since this is in the Power Query forum, I'd recommend

Date.StartOfMonth(DateTime.LocalNow()) - #duration(0,0,0,1)

In DAX, I'd recommend

EOMONTH ( TODAY(), -1 ) + TIME ( 23, 59, 59 )

[SuzieKidd]

Thank you I'll have a play with this.

[Anonymous]

Hi @SuzieKidd - Could you please explain what you are trying to achieve with this formula? 

Please note that the DAX DATEADD function does not support seconds, minutes and hours like its SQL cousin.  You may consider using the add duration functionality in Power Query, or add a DAX functions that convert datetime to seconds (a bit like UNIX Timestamp).

[SuzieKidd]

Thank you