SQL to DAX

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