Expression nested too deep issue

[Margaryta]

Hi everyone.

I have a gallery that I'd like to filter by multiple columns (in their different combinations), thus I have several input controls. 

The Items property of the gallery looks like this:

Sort(
     If(Not(IsBlank(Emp.Text)) && Not(IsBlank(Con.Text)) && IsBlank(Dep.Text) && _selectedCount=2 && wm_1_filter =1,
    Filter('[dbo].[welcome_meetings_view]','Start Date'>=sel_start.SelectedDate && 'Start Date'<=sel_end.SelectedDate && Emp.Text in Employee && Con.Text in country && wm_date_1<>Blank()),

    If(
    IsBlank(Emp.Text) && IsBlank(Con.Text) && IsBlank(Dep.Text) && _selectedCount<1 && wm_1_filter =0,
    '[dbo].[welcome_meetings_view]',

    If(Not(IsBlank(Emp.Text)) && IsBlank(Con.Text) && IsBlank(Dep.Text) && _selectedCount<1 && wm_1_filter =0,
    Search('[dbo].[welcome_meetings_view]', Emp.Text, "Employee"),

...............some more IFs....................
)))))))),
    'Start Date',SortOrder.Ascending)

At some point I started getting an error: Expression nested too deep. An expression in your formula is nested more than 50 levels.

Is there a chance to avoid this error or to filter the gallery another way? Thanks in advance.

[RandyHayes · Accepted solution]

@Margaryta 

Hard to tell without the complete formula.

In general, you should have 1 table returning function in your formula.  Use the criteria of the Filter to base your logic.  Lot's of If's in an Items formula will lead to pain.

Ex.

Sort(
    Filter('[dbo].[welcome_meetings_view]',
        (IsBlank(Emp.Text) || Emp.Text in Employee) &&
        (IsBlank(Con.Text) || Con.Text in country) &&
        (wm_date_1 = If(wm_1_filter=1, Blank(), "somethingElse")) &&
         etc...
    ),
    'Start Date', Ascending
)

I hope this is helpful for you.