I have added the non- clustered indexes to the query. is there any way i can reduce the execution time by doing any changes to the following Query? (SQL Funtion)

```
Alter function [dbo].[FnDashSyncSummaryCountnew](@date datetime)
returns @table table
(
ExecAccId int,
AreaSalesManagerAccId int,
SellingType varchar(20),
SalesRepCount int,
Initial int,
Miday int ,
DayEnd int,
InvoiceCount int,
InvoicedSR int ,
OrderPlacedSR int,
ScheduleCall int,
ProductiveCall int,
UnProductive int,
OrderCount int
)
as
begin
declare @Productive table
(
SalesRepAccId int,
CustomerId int,
SellingType bit
)
insert into @Productive
select * from
(
select SalesRepAccId, CustomerId, PreSellingRoute
from InvoiceHeader ih inner join SalesRepAcc s on s.Id=ih.SalesRepAccId
where convert(varchar,InvoiceDate,23)=convert(varchar,@date,23) and ih.Deleted=0 and s.PreSellingRoute=0
union
select SalesRepAccId, CustomerId, PreSellingRoute
from OrderRequestHeader oh inner join SalesRepAcc s on s.Id=oh.SalesRepAccId
where convert(varchar,TransactionDate,23)=convert(varchar,@date,23) and oh.Deleted=0 and s.PreSellingRoute=1
)s
declare @SyncDetails table
(
ExecAccId int,
AreaSalesManagerAccId int,
SalesRepAccId int,
SalesRepName varchar(50),
Initial varchar(50),
Miday varchar(50),
DayEnd varchar(50),
PreSellingRoute bit,
Battery int,
StartBatteryLevel int
)
insert into @SyncDetails
select * from FnDashSyncSummary(@date)
insert into @table
select ExecAccId, AreaSalesManagerAccId, SellingType, sum(SalesRepCount)SalesRepCount,
sum(Initial)Initial, sum(Miday)Miday, sum(DayEnd)DayEnd, sum(InvoiceCount)InvoiceCount,
sum(Invoiced)Invoiced, sum(OrderPlaced)OrderPlaced, sum(ScheduleCall)ScheduleCall,
sum(ProductiveCall)ProductiveCall, sum(UnProductive)UnProductive, sum(OrderCount)OrderCount
from
( --t2
select (select top 1 ExecAccId from Route r where r.SalesRepAccId=t1.SalesRepAccId and ExecAccId is not null)ExecAccId,
(select top 1 AreaSalesManagerAccId from Route r where r.SalesRepAccId=t1.SalesRepAccId)AreaSalesManagerAccId,
case when SellingType=1 then 'Pre Selling' else 'Direct Seliing' end as SellingType,
sum(SalesRepCount)SalesRepCount, sum(Initial)Initial, sum(Miday)Miday, sum(DayEnd)DayEnd, sum(InvoiceCount)InvoiceCount,
sum(Invoiced)Invoiced, sum(OrderPlaced)OrderPlaced, sum(ScheduleCall)ScheduleCall,
sum(ProductiveCall)ProductiveCall, sum(UnProductive)UnProductive, sum(OrderCount)OrderCount
from
( --t1
select SalesRepAccId, SellingType, count(distinct CustomerId)ProductiveCall, 0'UnProductive',
0'ScheduleCall', 0'Invoiced', 0'InvoiceCount', 0'OrderPlaced', 0'OrderCount', 0'SalesRepCount', 0'Initial', 0'Miday', 0'DayEnd'
from @Productive
group by SalesRepAccId, SellingType
union
select SalesRepAccId, PreSellingRoute, 0, count(distinct CustomerId)UnProductive,
0, 0, 0, 0, 0, 0, 0, 0, 0
from VisitDetail vd inner join SalesRepAcc s on vd.SalesRepAccId=s.Id
where convert(varchar,VisitDate,23)=convert(varchar,@date,23) and CustomerId not in (select distinct CustomerId from @Productive)
group by SalesRepAccId, PreSellingRoute
union
select r.SalesRepAccId, s.PreSellingRoute, 0, 0, count(c.Id)ScheduleCall, 0, 0, 0, 0, 0, 0, 0, 0
from (select Id, RouteId from Customer where Active=1)c inner join (select distinct v.RouteId from VisitHeader v
where convert(varchar,VisitDate,23)=convert(varchar,@date,23) and v.RouteId is not null)v on v.RouteId=c.RouteId
inner join Route r on c.RouteId=r.Id
inner join SalesRepAcc s on s.id=r.SalesRepAccId
group by r.SalesRepAccId , s.PreSellingRoute
union
select SalesRepAccId, PreSellingRoute, 0, 0, 0, 1'Invoiced',
count(ih.InvoiceNo)InvoiceCount, 0, 0, 0, 0, 0, 0
from InvoiceHeader ih inner join SalesRepAcc s on ih.SalesRepAccId=s.id
where convert(varchar,InvoiceDate,23)=convert(varchar,@date,23) and ih.PreOrder=0 and ih.Deleted=0
group by SalesRepAccId, PreSellingRoute
union
select SalesRepAccId, PreSellingRoute, 0, 0, 0, 0, 0, 1'OrderPlaced',
count(oh.OrderRequestId)OrderCount, 0, 0, 0, 0
from OrderRequestHeader oh inner join SalesRepAcc s on oh.SalesRepAccId=s.id
where convert(varchar,TransactionDate,23)=convert(varchar,@date,23) and oh.Deleted=0
group by SalesRepAccId, PreSellingRoute
union
select SalesRepAccId, PreSellingRoute, 0, 0, 0, 0, 0, 0, 0, sum(SalesRepCount)SalesRepCount,
sum(Initial)Initial, sum(Miday)Miday, sum(DayEnd)DayEnd
from
(
select SalesRepAccId, PreSellingRoute, count(distinct SalesRepAccId)SalesRepCount,
0'Initial', 0'Miday', 0'DayEnd'
from @SyncDetails
group by SalesRepAccId, PreSellingRoute
union
select SalesRepAccId, PreSellingRoute, 0, count(distinct SalesRepAccId)Initial, 0, 0
from @SyncDetails
where Initial<>''
group by SalesRepAccId, PreSellingRoute
union
select SalesRepAccId, PreSellingRoute, 0, 0, count(distinct SalesRepAccId)Miday, 0
from @SyncDetails
where Miday<>''
group by SalesRepAccId, PreSellingRoute
union
select SalesRepAccId, PreSellingRoute, 0, 0, 0, count(distinct SalesRepAccId)DayEnd
from @SyncDetails
where DayEnd<>''
group by SalesRepAccId, PreSellingRoute
)t
group by SalesRepAccId, PreSellingRoute
)t1
group by SalesRepAccId, SellingType
)t2
group by ExecAccId, AreaSalesManagerAccId, SellingType
order by AreaSalesManagerAccId
return
end
GO
```