I'm attempting retrieve a max version for either a published version or, if a resource has no published versions, the highest version. I'm using 3 CTE to find these values, one to get the max version that is published, a…
Consider the two models below: from django.db import models class Author(models.Model): name = models.CharField(max_length=255) class Book(models.Model): author = models.ForeignKey(Author, models.CASCADE, related_name="books") how to get only authors that does not have books?
I have a table and I want to select all unique values of all attributes in one query. For example table Person with 3 columns name, age, city. Example: Name age city Alex 34 New York Leo 34 London Roy…
I have the following data: id1 id2 score 281 33453 23 281 33452 23 281 36466 24 282 12118 14 282 27603 18 How do I write my query in PostgreSQL in the most efficient way so that I keep…
Can we create two (or more) columns in Postgres/ MySQL with the same name but a different case? As in does case-sensitivity matter in column names? For e.g., Can a table contain two columns with names - COL and col?…
I'm new to Python. I'm building a learning application that allows users to run sql queries on training tables directly from a browser. I am using FastAPI + Jinja2 + PostgreSQL. I am using ACE as a code editor. Is…
I have a table: select * from users id | name | company_name 1 | Sam | Sam's Plumbing 2 | Pat | Pat's Bakery 3 | Vic | I want to move users.company_name to a new companies table, with…
I'm trying to filter my table 'mange' with the condition of customers who eat both the "mexicaine" and the "végétarienne". I have a table 'mange' which contains 'nom' and 'pizza' I have tried to filter with select * from mange…
I am writing some SQL code where i have a comma separated string with 3 values. I would like to transform this string into an array and write it into the first 3 elements of a larger array. My naive…
To my understanding, database can postpone writing to table files to boost IO performance. When transaction is COMMITted, data are written to the WAL files. I'm curious, how much delayed the writing to table files can be. In particular, when…