I’ve set up the following table: CREATE TABLE transactions (txn_id SERIAL, stock VARCHAR NOT NULL, qty INT NOT NULL, user_id INT NOT NULL); On inserting few rows, the table looks like this: txn_id | …
Tag: sqlalchemy
Select row where column is different from previous row
I am trying to write a query to track the changes of a boolean column in a table. The table looks like this So what i would want is row 3 where the is_active changed to false. Then after that i would want the next row where it changed to true again. This is what i tried: So the subquery
Python problem with adding table to Database with sql
Hi, I’m trying to create a function that will take a table in insert(add) to the database. My Code : this is the old code when i didn’t create a function: Answer You seem to have put table_name under quotations in your to_sql function. Also, you seem to be tackling the issue of data model creation and mainten…
How to create sql db2 data table using python?
I would like to run an sql db2 query on python that will create a data table in a public schema but I’m stuck because of this error ResourceClosedError: This result object does not return rows. It …
SQLAlchemy – How to count distinct on multiple columns
I have this query: I’ve tried to recreate it with SQLAlchemy this way: But this translates to this: Which does not call the count function inline but wraps the select distinct into a subquery. My question is: What are the different ways with SQLAlchemy to count a distinct select on multiple columns and …
Python SQL: Error reading and executing SQL file
I’m trying to red and execute a SQL file in Python using sqlalchemy. Should be simple, right? I get this error Why am I getting this error? I’m not sure if this is a file encoding error or a SQLAlchemy error. Ideally, this should be simple. EDIT: This code works fine, assuming the table temp exist…
sqlalchemy concat with more than 2 elements on Oracle DB
considering the following table definition I create a select-statement using the sqlalchemy.sql.functions.concat with 3 statements using the query is generated. However, when I run this, the exception ORA-00909: invalid number of arguments is thrown. This is because CONCAT (https://docs.oracle.com/cd/B19306_0…
How do I select a PostgreSQL system column using SQLAlchemy?
Postgresql implicitly defines several columns on every table, such as xmax and ctid (see docs). Assuming my SQLALchemy table definition does not specify these columns, is there a way to select them using the core sql functionality (i.e. not the ORM part of SA)? The following does not work as xmax is not expli…
Conditional Join Between SQL Table and Pandas Dataframe
I am working on an application and one step of the processing involves joining drug NDC’s from claim data with a table that contains the NDC along with a variety of other information including unit price, multisource code, and more. The table of claims data looks something like this: It was read into a …
Is it possible to create custom “Columns” in SQLAlchemy? is this breaking OOP?
I’m new in SQLAlchemy and I’m trying to understand some concepts. Here is a code example without SQLAlchemy: class Token: def __init__(self, key): # generate token based on a string …