Скачать или смотреть How to Use Python to Update SQL Tables Efficiently with UPDATE Statements

Learn how to loop through SQL result sets and update records in Python with an effective method. Stay efficient and improve your database interactions!
---
This video is based on the question https://stackoverflow.com/q/72300488/ asked by the user 'Rohan' ( https://stackoverflow.com/u/19091613/ ) and on the answer https://stackoverflow.com/a/72303700/ provided by the user 'Almos' ( https://stackoverflow.com/u/19101368/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Python Script to run SQL query UPDATE statement to loop through each row in result set and update columns

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Use Python to Update SQL Tables Efficiently with UPDATE Statements

When working with databases using Python, you may find yourself needing to loop through a set of results and update records based on specific conditions. This scenario often arises when using two related tables, especially when one table serves as a master table while the other contains more detailed entries. In this post, we will explore how to tackle a common problem: updating the records in a master table based on the latest statuses found in a list table using Python and SQL.

The Problem

Imagine you have two tables: t1 (the master table) and t2 (the detail table). Here’s a breakdown of their structures:

Table Structure

Table 1 (t1): Contains unique project IDs and three status columns

project_id, status1, status2, status3

Table 2 (t2): Contains multiple entries for each project along with their respective statuses

recordid, project_id, status1, status2, status3

As you execute your Python script, you want to loop through each unique project ID in t1, fetch the latest status from t2, and then update t1 accordingly.

The Solution

Let's break down the steps to achieve this in an organized manner.

Step 1: Database Connection

To start, you need to establish a connection to your database.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Fetch Unique Project IDs

Next, we will retrieve all unique project IDs from t1.

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Loop Through Results and Fetch Latest Status

Now, we need to loop through the results from t1, fetching the latest entry from t2 for each project ID based on its recordid.

[[See Video to Reveal this Text or Code Snippet]]

Step 4: Update t1 with Latest Status

Finally, if you successfully fetched the latest status for a particular project, you can now update the t1 table accordingly.

[[See Video to Reveal this Text or Code Snippet]]

Full Python Script Example

Below is the full Python script that combines all the steps outlined above:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these steps, you can efficiently update values in your SQL database tables using Python. The key takeaway is to use parameterized queries for secure and efficient database interactions. This method will also help you maintain clean and readable code in your projects. Happy coding!