sql exec

Exec sintax on sql server usually use to execute parameter

see example below:
select ('soemaryanto')usr_name,('admin')access_sttus,('active')active_status

#Results:
usr_name       access_sttus    active_status
soemaryanto    admin           active

declare @qry nvarchar(100)
set @qry=('select (''soemaryanto'')usr_name,(''admin'')access_sttus,(''active'')active_status')
select (@qry)text_qry


exec (@qry)

#Results:
text_qry
select ('soemaryanto')usr_name,('admin')access_sttus,('active')active_status

usr_name       access_sttus    active_status
soemaryanto    admin           active

another example exec sql server statement
declare @count int
declare @qry nvarchar(100)
declare @qryBuffer nvarchar(200)
set @count=0
set @qry=''
set @qryBuffer=''

WHILE not @count =10
BEGIN
    set @count=@count+1
    if @qryBuffer=''
        set @qryBuffer=('select ('+convert(nvarchar,@count)+')AutoNum')
    else
        set @qryBuffer=@qryBuffer+' union '+('select ('+convert(nvarchar,@count)+')')
END
exec (@qryBuffer)

#Results:
AutoNum
1
2
3
4
5
6
7
8
9
10