完全更新临时表SQL

Question

我有一个问题:我试图在SQL Server 2012中完全更新临时表(在存储过程中)，但它只更新与我的描述匹配的第一个条目。下面是代码:

create table #t (store_name varchar(30),
                 product_name varchar(30), 
                 price int, 
                 valab_since date, 
                 valab_until date, 
                 best_offer varchar(3))
--some code that populates my table
update #t set best_offer = 'yes'
where price = (select min(price) from Cataloage as c 
                INNER JOIN Produse as p
                on c.codP = p.codP
                where p.denumire = #t.store_name)
update #t set best_offer = 'no'
where price > (select min(price) from Cataloage as c 
                INNER JOIN Produse as p
                on c.codP = p.codP
                where p.denumire = #t.product_name)
select * from #t

Cataloage和Produse是我使用的一些表

Answer 1

要覆盖所有记录，首先将它们全部设置为"no"，然后运行单独的查询，仅更新具有商店最小价格的记录。

update #t set best_offer = 'no';
;with t as (
    select *, rnk = dense_rank() over (partition by t.store_name order by price asc)
    from Cataloage c
    join Produse p on c.codP = p.codP
    join #t t on p.denumire = t.store_name
)
update t
set best_offer = 'yes'
where rnk = 1;

我使用了DENSE_RANK和一个公共表表达式作为逐行子查询的替代方法。