SQL 比较两个不同表中的列
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Compare a column in two different tables
提问by ad2387
Say I have two tables, Table A and Table B, and I want to compare a certain column.
假设我有两个表，表 A 和表 B，我想比较某个列。
For example,
例如，
Table A has the columns: IP,Host,App
表 A 包含以下列：IP、Host、App
Table B has the columns: IP,Datacenter,Server,Model,Last_Updated
表 B 有以下列：IP,Datacenter,Server,Model,Last_Updated
How do I compare the IP column between the two tables to get the differences?
如何比较两个表之间的 IP 列以获取差异？
I know if the tables have the same columns I can use a union and 'minus' to get the differences but I wasn't able to figure out a way if the tables have different columns.
我知道如果表具有相同的列，我可以使用联合和“减号”来获取差异，但是如果表具有不同的列，我无法找出一种方法。
Thanks!
谢谢！
回答by Quassnoi
SELECT *
FROM A
FULL JOIN
B
ON a.IP = b.IP
WHERE a.IP IS NULL OR b.IP IS NULL
This will output all columns from non-matching rows in both tables, with NULLs on either side.
这将输出两个表中不匹配行的所有列，两边都有 NULL。
回答by Nitin
select distinct column_A FROM table_1 where column_A not in (SELECT column_A FROM table_2)
回答by Brian
you mean you want to get all IPs in table A that are not in table B?
您的意思是要获取表 A 中不在表 B 中的所有 IP？
select IP from table A
MINUS
select IP from table B
Did I understand the question correctly?
我是否正确理解了问题？
