Re: How to compare two tables in PostgreSQL

From: saikiran mothe [mailto:saikiran(dot)mothe(at)gmail(dot)com]
Sent: Saturday, November 10, 2012 10:14 PM
To: pgsql-sql(at)postgresql(dot)org
Subject: How to compare two tables in PostgreSQL

Hi,

How can i compare two tables in PostgreSQL.

Thanks,
Sai

Here is simple sql to show data in table1, but not in table2:

SELECT <common_column_list> from table1
EXCEPT
SELECT <common_column_list> from table2;

And this sql shows data in table2 but not in table1:

SELECT <common_column_list> from table2
EXCEPT
SELECT <common_column_list> from table1;

Or, you could combine them in one statement, adding "indicator" column:

SELECT <common_column_list>, 'not in table2' as indicator from table1
EXCEPT
SELECT <common_column_list>, 'not in table2' as indicator from table2
UNION
SELECT <common_column_list>, 'not in table1' as indicator from table2
EXCEPT
SELECT <common_column_list>, 'not in table1' as indicator from table1;

Regards,
Igor Neyman