Question is simple. How to add column x to table y, but only when x column doesn’t exist ? I found only solution here how to check if column exists. SELECT column_name FROM information_schema.columns WHERE table_name=”x” and column_name=”y”; 11 Answers 11
I have a small table and a certain field contains the type “character varying“. I’m trying to change it to “Integer” but it gives an error that casting is not possible. Is there a way around this or should I just create another table and bring the records into it using a query. The field … Read more
I’m getting the following error when running a query on a PostgreSQL db in standby mode. The query that causes the error works fine for 1 month but when you query for more than 1 month an error results. ERROR: canceling statement due to conflict with recovery Detail: User query might have needed to see … Read more
I either forgot or mistyped (during the installation) the password to the default user of Postgres. I can’t seem to be able to run it and I get the following error: psql: FATAL: password authentication failed for user “hisham” hisham-agil: hisham$ psql Is there anyway to reset the password or how do I create a … Read more
I have a table that looks like this caller ‘makerar’ cname | wmname | avg ——–+————-+———————— canada | zoro | 2.0000000000000000 spain | luffy | 1.00000000000000000000 spain | usopp | 5.0000000000000000 And I want to select the maximum avg for each cname. SELECT cname, wmname, MAX(avg) FROM makerar GROUP BY cname; but I will get … Read more
When I do a \dt in psql I only get a listing of tables in the current schema (public by default). How can I get a list of all tables in all schemas or a particular schema? 5 Answers 5
What command or short key can I use to exit the PostgreSQL command line utility psql? 8 Type \q and then press ENTER to quit psql. UPDATE: 19-OCT-2018 As of PostgreSQL 11, the keywords “quit” and “exit” in the PostgreSQL command-line interface have been included to help make it easier to leave the command-line tool.
