sql server - SQL - SELECT rows conditionally -

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the following criteria select rows:

  • for same sysid, p2 preferred p1.

i came logic 

    declare @products table     (         id int,         sysid varchar(100)               );      insert @products     select id, sysid productmain     productcode = 'p2'      insert @products     select id, sysid productmain productcode = 'p1'     , sysid not in (select sysid @subscription)      --result     select id,sysid @products

sample data

id  sysid  productcode 1   121    p1 2   121    p2 3   122    p1 4   123    p2 5   124    p1 6   124    p2

desired output

id  sysid 2   121 3   122 4   123 6   124

i know there should better logic this. please help. in advance.

if p1, p2 not actual data, change order by case when productcode = 'p2' 1 else 2 end

select * (    select *, rn = row_number() on (partition sysid order productcode desc)      yourtable ) d d.rn = 1

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