How to join two tables without any condition

问题

For example I have two tables (temp tables). One of them contains only IDs, and the other contains real information. They have exactly the same row number.

#Table1
ID
14
15
16

#Table2
CarModel    Year
Ford        1996
Ferrari     2005
Toyota      2010

How can I join this two table in one (without any condition, just the result table has 3 columns, no matter in what order)? I need it for inserting the result for real table

Cars
ID   CarModel   Year

And this table doesn't use identity. There is an own mechanism of getting IDs for inserting. I'm not able to change it.

So as a result I need a table like one of the following (ordering is NOT important):

#Table3
ID   CarModel    Year
14   Ford        1996
15   Ferrari     2005
16   Toyota      2010

#Table3
ID   CarModel    Year
16   Ford        1996
14   Toyota      2010
15   Ferrari     2005

P.S. I understand how to do this with CTE and row_number(), but I think there is more easier way to do this task. And may be this code will be used in MS SQL Server 2000, so I will be glad to look at other variants of the solutions.

回答1:

Here's a triangular join that would work in SQL Server 2000 per Martin Smith's comment:

-- Some test data:
declare @Table1 table (
    ID int primary key
)
insert into @Table1 select 14
insert into @Table1 select 15
insert into @Table1 select 16

declare @Table2 table (
    CarModel varchar(50) not null,
    [Year] smallint not null
)
insert into @Table2 select 'Ford', 1996
insert into @Table2 select 'Ferrari', 2005
insert into @Table2 select 'Toyota', 2010

-- Here's the actual query:
select Table1.ID, Table2.CarModel, Table2.[Year]
from (
        select ID, (select count(*) from @Table1 where ID < a.ID) as JoinPredicate
        from @Table1 as a
    ) as Table1
    join (
        select CarModel, [Year], (select count(*) from @Table2 where CarModel < a.CarModel or (CarModel = a.CarModel and [Year] < a.[Year])) as JoinPredicate
        from @Table2 as a
    ) as Table2 on Table1.JoinPredicate = Table2.JoinPredicate

Of course, this assumes that Table1.ID is unique and Table2.CarModel + Table2.Year is unique.

The performance considerations of triangular joins are discussed nicely here: http://www.sqlservercentral.com/articles/T-SQL/61539/

来源：https://stackoverflow.com/questions/8916118/how-to-join-two-tables-without-any-condition

标签

sql

sql-server

join

sql-server-2000