how to use if else condition in sqlserver

How to use if else in sqlserver

This is my code  you can see below:
I hope this will help full to you

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER procedure [dbo].[CCISales_Groupwise]

@From varchar(50),
@To varchar(50),
@Exid varchar(50),
@ExName varchar(50)
as
begin
if @Exid!='All'
Begin
select distinct  cdp.Exhibition_Id,cdp.Exhibition_Name, convert(Varchar(50),cdp.Added_On,103) AS dates,CDP.GroupMode,
(SELECT SUM(Product_Total) FROM CCISold_Product_Details WHERE GROUPMODE=CDP.GROUPMODE and convert(Varchar(50),Added_On,103)=convert(Varchar(50),cdp.Added_On,103) and Exhibition_Id like case when @Exid='All' then '%%' else '%'+@Exid end and Exhibition_Name like case when @ExName='All' then '%%' else '%'+@ExName end
)AS PRODUCT,(SELECT COUNT(*) FROM CCISold_Product_Details WHERE GROUPMODE=CDP.GROUPMODE and convert(Varchar(50),Added_On,103)=convert(Varchar(50),cdp.Added_On,103) and Exhibition_Id like case when @Exid='All' then '%%' else '%'+@Exid end and Exhibition_Name like case when @ExName='All' then '%%' else '%'+@ExName end
)AS Qty  from CCISold_Product_Details AS CDP where Exhibition_Id like case when @Exid='All' then '%%' else '%'+@Exid end and Exhibition_Name like case when @ExName='All' then '%%' else '%'+@ExName end
group by Exhibition_Id, Exhibition_Name,convert(Varchar(50),cdp.Added_On,103),CDP.GroupMode
End
Else
begin
select distinct 
 convert(Varchar(50),cdp.Added_On,103) AS dates,CDP.GroupMode,
(SELECT SUM(Product_Total) FROM CCISold_Product_Details WHERE GROUPMODE=CDP.GROUPMODE and convert(Varchar(50),Added_On,103)=convert(Varchar(50),cdp.Added_On,103) and Exhibition_Id like case when @Exid='All' then '%%' else '%'+@Exid end and Exhibition_Name like case when @ExName='All' then '%%' else '%'+@ExName end
)AS PRODUCT,(SELECT COUNT(*) FROM CCISold_Product_Details WHERE GROUPMODE=CDP.GROUPMODE and convert(Varchar(50),Added_On,103)=convert(Varchar(50),cdp.Added_On,103) and Exhibition_Id like case when @Exid='All' then '%%' else '%'+@Exid end and Exhibition_Name like case when @ExName='All' then '%%' else '%'+@ExName end
)AS Qty  from CCISold_Product_Details AS CDP where Exhibition_Id like case when @Exid='All' then '%%' else '%'+@Exid end and Exhibition_Name like case when @ExName='All' then '%%' else '%'+@ExName end
group by convert(Varchar(50),cdp.Added_On,103),CDP.GroupMode
end
--select distinct @From as frd,@To as Tod, cdp.Exhibition_Id,cdp.Exhibition_Name, convert(Varchar(50),cdp.Added_On,103) AS dates,CDP.GroupMode,
--(SELECT SUM(Product_Total) FROM CCISold_Product_Details WHERE GROUPMODE=CDP.GROUPMODE and convert(Varchar(50),Added_On,103)=convert(Varchar(50),cdp.Added_On,103)
--)AS PRODUCT,(SELECT COUNT(*) FROM CCISold_Product_Details WHERE GROUPMODE=CDP.GROUPMODE and convert(Varchar(50),Added_On,103)=convert(Varchar(50),cdp.Added_On,103)
--)AS Qty  from CCISold_Product_Details AS CDP where Exhibition_Id like case when @Exid='All' then '%%' else '%'+@Exid end and Exhibition_Name like case when @ExName='All' then '%%' else '%'+@ExName end
--group by Exhibition_Id, Exhibition_Name,convert(Varchar(50),cdp.Added_On,103),CDP.GroupMode
end