Consider a table with an id PK and 26 columns. There is an index on (a,b) I’m trying to select the row where the unique pairing of (a,b) is most recent. IE what was the last record for each (a,b) Because ID is autoincrementing, know that the max is the last row. However, is there any way to have the
Tag: python
Obtain count of non null values by casting a string column as type integer in pyspark – sql
I have an rdd with string columns, but I want to know if a string column has numeric values. Looking for a very inexpensive way to do this, I have many tables with millions of records. For example, I’ve tried casting the column to int, float, etc, but I get all null values, so count is always zero: returns values
inserting to database from query in python
I have a table of tweet data my_tweets containing these columns: tweet_id, text, created_at, sentiment My tweet data is being streamed live and simultaneously inserted into the table. I am writing code using Vader to get the sentiment of the text. At the moment, tweet_id, text, and created_at are all populated. I would like to use this query: SELECT *
Variables in SQLITE Python
I am working in Jupyter Notebooks using pandasql, which uses SQLight syntax. I am trying to select entries from a certain month, depending on a variable. I am planning to create a Python function that will change the value of the variable being used, but right now I am trying to get “Parameterized Queries” to work. My table has the
Django: How to mangle through relations
I have an instance of ModelA and want to query all instances of ModelC which are related to ModelA through ModelB. ModelA -> all ModelB instances with FK rel_a = ModelA -> rel_c.all() I know how I would do this in SQL but I really do not get how I should unmangle these relations Answer You can query with a
SQLAlchemy: Filter the Objects From Relationship When Accessed
Query Statement: Get Children that have their Names start with ‘A’. Link Them With their Parents. Schema: I Have a One-to-Many Relationship. Parent(id, Name, children(rel->child)) -> Child(id, …
cs50 pset7 houses syntax
I’m working on the roster.py part of the problem and I’m getting the error: My code: Answer Your quotes are wrong. Try this:
Django sql statements with non english symbols
I have sql statement, with non english symbols in where (sap_code variable contains russian text) sap_code = ‘ОВОЩИ – ФРУКТЫ’ sql_string = ‘SELECT ‘ ‘SAP_CODE, ‘ ‘SKU, ‘ …
Python/Excel/SQL column dates to exploded rows
I have an Excel spreadsheet table like this where it shows how many units were sold each week for 2019 and 2020 (columns) and I am trying to put it into an access database formatted like the second …
SQL – Conditionally join and replace values between two tables
I have two tables where one is holding “raw” data and another is holding “updated” data. The updated data just contains corrections of rows from the first table, but is essentially the same. It is a functional requirement for this data to be stored separately. I want a query with the following conditions: Select all rows from the first table