I am trying to create few tables in Postgres from pandas dataframe but I am kept getting this error. psycopg2.errors.InvalidForeignKey: there is no unique constraint matching given keys for …
Tag: postgresql
Postgres: Mathematical functions in COALESCE
I have a table which contains ID column: ID — 1 2 3 4 5 I have to retrieve an ID using a simple query. If the ID is not present in the table, then I want to display ID – 1 For example, In the above …
Order by descending aggregation within window function in PostgreSQL
I have a dataset that features duplicate values of the the primary variable, something like the following: I have achived this by using the following code However, my desired output needs to be ordered such that counts is descending yet col1 remains partitioned, so that I can see, for example, which value from col1 has the highest number of counts.
How to build a query so that I can find all events along with an extra bool column “attending” which is a join on attendees table?
I have a events table, and I have a events_attendees table which has the event_id and user_id. For example, I want to find events around some user (user_id = 1) but also know whether or not they are attending through that additional column. Here’s the query that would get me the pins where the user is attending, but again I
Understand the logical query processing when ‘Between’ condition is used in a self join of a SQL query
I have the following Orders table in PostgreSQL Database I need to return the cumulative sum of revenue for every order_date from last 2 days including the revenue for that order date. I am using the following query and it returns following result As per logical order of the query processing following steps will be performed The ‘JOIN’ will first
Multiple select statements in single query while using ‘group by’ and ‘join’
I have three tables – podcasts, videos and others. Each of the entities under these are associated with a category and subcategories. Example for podcasts – This category_id and subcategory_id have their name values in their respective tables – Now, I want to get the count of podcasts, videos and text under each category & subcategory combination. My individual SQL
Select in return for postgres query
is it possible to add a select in a return statement? I tried adding the select name from skills where skill_id = 1 but not sure if this is possible or I just don’t have the syntax right. Answer Yes, that is possible, but you have to enclose a subquery in parentheses:
PSQL query to insert the records from one table to another based on condition
I have 2 Postgres tables with the following structure: Lets say I have data in the tmp table as below: Now I want to write a psql INSERT INTO query which will copy the data from public.tmp to public.mo table and also perform below condition When a Host has mix values in STATUS column, for eg if HOST: RhelTest has
Oracle decode equivalent function to Postgres
So, I’m in migrating database from oracle to Postgres, and this is my error: and here’s my code : do you have any clue? From what I’ve read, some say to replace the decode function with COALESCE, but I don’t have any idea how the syntax is. Answer You could use a standard case expression:
Postgresql how to select columns where it matches conditions?
I have a table like this: I want to select rows where most recent date with corresponding columns, This is what I want to achieve: I tried to use aggregate but I need inventory_id and customer_id appear at the same time. Is there any method that could do this? Answer Use distinct on: distinct on is a Postgres extension that