Question

in buy table . when customer buy same book 1 row add to table . so when see buy list in buy page its like this :

buy1 price1 downloadlink1
buy1 price1 downloadlink1
buy1 price1 downloadlink1
buy2 price2 downloadlink2
buy2 price2 downloadlink2
buy2 price2 downloadlink2

but i want in same row price and downloadlink delete and only first row show this value
like this :

buy1 price1 downloadlink1
buy1 
buy1 
buy2 price2 downloadlink2
buy2 
buy2 

how can i use sql query???

Answer 1

well if it would be MS SQL server I could suggest using row_number over()
But in your situation I can suggest try this (I suppose you have some id in your table)

select
    A.sub,
    case when A.frst = 1 then A.user else null end as user,
    case when A.frst = 1 then A.versionid else null end as versionid,
    case when A.frst = 1 then A.hard else null end as hard,
    case when A.frst = 1 then A.active else null end as active,
    case when A.frst = 1 then A.res else null end as res
from
(
    select
        *,
        case
            when exists
            (
                select * 
                from buy as tt
                where
                    tt.sub = t.sub and tt.res = t.res and
                    tt.user = t.user and tt.versionid = t.versionid and
                    tt.hard = t.hard and tt.active = t.active and
                    tt.id < t.id
            ) then 0
            else 1
        end as frst
    from buy as t
) as A
order by A.sub, A.frst desc

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