sql-server - 完全更新临时表 SQL

Question

我有一个问题：我正在尝试完全更新 SQL Server 2012 中的临时表（在存储过程中），但它只更新与我的描述匹配的第一个条目。这是代码：

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并且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“否”，然后运行单独的查询以更新商店的最低价格。

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 DENSE_RANK 和一个公共表表达式作为逐行子查询的替代方法。