how to get values for same column name from two different tables in SQL

问题

How to get values for same column name from two different tables in SQL?

column name is emp_id loacated in these two tables: company,employee.

回答1:

If you want data in seperate columns from two tables then try :

SELECT c.emp_id, emp.emp_id 
FROM company c
INNER JOIN employee emp on c.company_id = emp.company_id 

If you want to merge both columns data then use this :

SELECT emp_id FROM company
UNION
SELECT emp_id FROM employee

回答2:

Use this to get the results:

company.emp_id, employee.emp_id

回答3:

You can do what you are asking, something like the example below, but if you provide a sample query, it would help...

select emp.emp_id,company.emp_id
from company
join employee emp on emp.company_id=company_company_id

回答4:

Just put the name of the table before the name of the colomn with a "." between, like:

SELECT company.emp_id, employe.emp_id

来源：https://stackoverflow.com/questions/7513669/how-to-get-values-for-same-column-name-from-two-different-tables-in-sql