[英]join tables that have different column with the same data
我有三个表收集器、销售员和客户,每个表的第一列都有不同的列,但里面有相同的数据,如下所示:
顾客:
|---------------------|------------------|
| cust# | cust_name |
|---------------------|------------------|
| 12 | a |
|---------------------|------------------|
| 5 b
|---------------------|------------------|
| 10 | c |
|---------------------|------------------|
销售员:
|---------------------|------------------|
| sal# | sales_name |
|---------------------|------------------|
| 12 | t |
|---------------------|------------------|
| 5 s
|---------------------|------------------|
| 10 | v |
|---------------------|------------------|
收藏家:
|---------------------|------------------|
| coll# | coll_name |
|---------------------|------------------|
| 12 | r |
|---------------------|------------------|
| 5 k
|---------------------|------------------|
| 10 | z |
|---------------------|------------------|
我需要知道如何连接这三个表并为第一列命名如下:
|---------------------|------------------|-------------------|----------------|
| given_name# | cust# | sales_name coll_name
|---------------------|------------------|-------------------|----------------|
| 12 | a | t r
|---------------------|------------------|-------------------|----------------|
| 5 b s k
|---------------------|------------------|-------------------|----------------|
| 10 | c | v z
|---------------------|------------------|-------------------|----------------|
任何帮助将不胜感激
您可以在这些表中使用INNER JOIN
:
SELECT c.coll# AS given_name#, cs.cust_name AS cust#, s.sales_name, c.coll_name
FROM collectors c
JOIN salesman s
ON c.coll# = sal#
JOIN customer cs
ON c.coll# = cs.cust#
PS:如果你的DBMS是MySQL,那么包含#
字符的列应该用反引号(`)来引用,比如
`given_name#` or `sal#` ..etc.
每个 id 在所有三个表中总是有一行吗? 如果是这样,您可以只使用 1 个带有 AS 的列
SELECT `sal#` as `given_name#`
尝试这个..
--********************************
if object_id('customer') is not null
begin
drop table customer
end
go
create table [dbo].[customer](
[id] [int] identity(1,1) not null,
[cust] [int] not null,
[cust_name] [varchar](20) not null)
go
insert into customer (cust, cust_name) values (12, 'a')
insert into customer (cust, cust_name) values (5, 'b')
insert into customer (cust, cust_name) values (10, 'c')
go
if object_id('salesmen') is not null
begin
drop table salesmen
end
go
create table [dbo].[salesmen](
[id] [int] identity(1,1) not null,
[sal] [int] not null,
[sales_name] [varchar](20) not null
)
go
insert into salesmen (sal, sales_name) values (12, 't')
insert into salesmen (sal, sales_name) values (5, 's')
insert into salesmen (sal, sales_name) values (10, 'v')
go
if object_id('collectors') is not null
begin
drop table collectors
end
go
create table [dbo].[collectors](
[id] [int] identity(1,1) not null,
[coll] [int] not null,
[coll_name] [varchar](20) not null
)
go
insert into collectors (coll, coll_name) values (12, 'r')
insert into collectors (coll, coll_name) values (5, 'k')
insert into collectors (coll, coll_name) values (10, 'z')
go
--********************************
select dbo.customer.cust 'given_name', dbo.customer.cust_name 'cust', dbo.salesmen.sales_name 'sales_name', dbo.collectors.coll_name 'coll_name'
from dbo.collectors inner join dbo.customer on dbo.collectors.coll = dbo.customer.cust inner join dbo.salesmen on dbo.customer.cust = dbo.salesmen.sal
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