Active Account count on specific date in MDX - mdx

Question

I have a situation where I need to get active account count on a specific date.
I have start date end date in SQL it looks like
select count(account) where start_date <=#date and end_date >=#date
In MDX, I tried below one
AGGREGATE(
{
NULL:LINKMEMBER
(
[DATE].[YQMWD].CURRENTMEMBER
, [StartDate].[YQMWD]
)
}
*
{
LINKMEMBER
(
[DATE].[YQMWD].CURRENTMEMBER
, [EndDate].[YQMWD]
):NULL
}
, ([Measures].[AccountCount])
)
This Code is returning me perfect on date level only but once I am traversing to Week or Month it is considering the whole month of the active value. But during the selected month period many account getting deactivate.
If anybody faced this kind of measure before like
"Active value on specific date" .

Answer 1

I thought about the following but then noticed that you are dealing with two distinct dimensions [StartDate] and [EndDate] so using the range operator : is incorrect:
AGGREGATE(
UNION(
{
NULL
:
LINKMEMBER(
[DATE].[YQMWD].CURRENTMEMBER
, [StartDate].[YQMWD]
)
}
,{
LINKMEMBER(
[DATE].[YQMWD].CURRENTMEMBER
, [EndDate].[YQMWD]
)
:
NULL
}
)
, ([Measures].[AccountCount])
)
If we look in the definition of LINKMEMBER then it says the following:
https://msdn.microsoft.com/en-us/library/ms146058.aspx
The LinkMember function returns the member from the specified
hierarchy that matches the key values at each level of the specified
member in a related hierarchy. Attributes at each level must have the
same key cardinality and data type. In unnatural hierarchies, if there
is more than one match for an attribute's key value, the result will
be an error or indeterminate.
So it makes sense the behaviour you are encountering - if [DATE].[YQMWD].CURRENTMEMBER is a week, then the key of this member is not going to map across to either [StartDate].[YQMWD] or [EndDate].[YQMWD].
Moreover if a week is selected then how do you interpret this sql logic where start_date <=#date and end_date >=#date as a week is made up of 7 days so #date has 7 possibilities?
Maybe you could use EXISTS function inside the LINKMEMBER function so that only Date level members are used. Then we have this problem that Exists will return a set type but the first arg of LINKMEMBER needs to be of type member. So get hold of the first and last members using Tail and Head like so:
AGGREGATE(
{
NULL
:
LINKMEMBER(
HEAD(
EXISTS(
[DATE].[YQMWD].CURRENTMEMBER
,[DATE].[YQMWD].[Date] ////<<if CURRENTMEMBER is a week then Exists will return a set of 7 Date members
)
,1 ////<<if CURRENTMEMBER is a week then Head(..1) will return a set of 1 Date member - the first date in the week
).ITEM(0).ITEM(0) ////<<this converts from single member set to a member
, [StartDate].[YQMWD]
)
}
*
{
LINKMEMBER(
TAIL(
EXISTS(
[DATE].[YQMWD].CURRENTMEMBER
,[DATE].[YQMWD].[Date]
)
,1
).ITEM(0).ITEM(0)
, [EndDate].[YQMWD]
)
:NULL
}
, ([Measures].[AccountCount])
)

Answer 2

How about first checking for the type of input and then giving results? In this case CoalesceEmpty will check that and return the results. Used FirstChild function to fetch the first date always from the range.
CoalesceEmpty
(
AGGREGATE
(
{NULL:LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER.FIRSTCHILD.FIRSTCHILD.FIRSTCHILD.FIRSTCHILD, [StartDate].[YQMWD])}
*
{LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER.FIRSTCHILD.FIRSTCHILD.FIRSTCHILD.FIRSTCHILD, [EndDate].[YQMWD]):NULL}
, ([Measures].[AccountCount])
)//--If it is a year
,
AGGREGATE
(
{NULL:LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER.FIRSTCHILD.FIRSTCHILD.FIRSTCHILD, [StartDate].[YQMWD])}
*
{LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER.FIRSTCHILD.FIRSTCHILD.FIRSTCHILD, [EndDate].[YQMWD]):NULL}
, ([Measures].[AccountCount])
)//--If it is a quarter
,
AGGREGATE
(
{NULL:LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER.FIRSTCHILD.FIRSTCHILD, [StartDate].[YQMWD])}
*
{LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER.FIRSTCHILD.FIRSTCHILD, [EndDate].[YQMWD]):NULL}
, ([Measures].[AccountCount])
)//--If it is a month
,
AGGREGATE
(
{NULL:LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER.FIRSTCHILD, [StartDate].[YQMWD])}
*
{LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER.FIRSTCHILD, [EndDate].[YQMWD]):NULL}
, ([Measures].[AccountCount])
)//--If it is a week
,
AGGREGATE
(
{NULL:LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER, [StartDate].[YQMWD])}
*
{LINKMEMBER([DATE].[YQMWD].CURRENTMEMBER, [EndDate].[YQMWD]):NULL}
, ([Measures].[AccountCount])
)//--If it is a date
)