How to Use pg-promise for Date Filtering in PostgreSQL

Learn how to efficiently select records based on a date filter using `pg-promise` with PostgreSQL, avoiding common pitfalls like the 'operator does not exist' error.
---
This video is based on the question https://stackoverflow.com/q/63567036/ asked by the user 'mouchin777' ( https://stackoverflow.com/u/9010895/ ) and on the answer https://stackoverflow.com/a/63570191/ provided by the user 'GMB' ( https://stackoverflow.com/u/10676716/ ) 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: pg-promise , how to select with a where ... like date%

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 pg-promise for Date Filtering in PostgreSQL

When working with databases, it's common to find yourself needing to fetch records based on specific criteria. In this guide, we’ll dive into a particular issue faced when using pg-promise to select records based on a date. We'll explore what went wrong and how to effectively address it.

The Problem: Date Filtering with pg-promise

Imagine you have a database table that logs transactions with various details including an id, balance, and a datetime field indicating when the transaction occurred. The goal is to retrieve records where the datetime starts with a specific date. However, when attempting to construct your SELECT query, you run into an error message:

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

This issue arises from misunderstandings about how to handle date comparisons in SQL and the correct usage of query parameters in pg-promise.

The Solution: Correctly Querying Dates

To solve the problem effectively, we’ll break down the solution into clear steps that ensure you retrieve your desired results without errors.

Understanding Your Data

Firstly, let's recognize the structure of your data:

ID: An integer representing the unique identifier for the record.

Balance: An integer showing the account balance.

Datetime: A timestamp indicating when the transaction took place.

Avoiding LIKE for Date Comparisons

In the original query, the usage of LIKE was inappropriate for the datetime field, which is of type timestamp. Instead of string functions, we should leverage date functions which are more suited for this type of data.

Revised SQL Query

The correct way to fetch records where datetime falls on a specific date is to use a combination of greater than or equal (>=) and less than (<) comparisons:

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

Implementing in pg-promise

Now, let’s see how to implement this in your JavaScript code using pg-promise:

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

Key Takeaways

Use Date Functions: Instead of string functions like LIKE, use date comparisons for better accuracy.

Proper Parameter Usage: When using parameters in SQL through pg-promise, avoid surrounding them with single quotes.

Understand Your Data Types: Knowing the data type (like timestamp in this case) can help you choose the right SQL functions and operators.

Conclusion

By restructuring your SQL query to use correct date comparisons, you can eliminate errors and successfully retrieve records based on the datetime. This approach ensures better performance and accuracy when querying your database.

Now you can efficiently filter transaction records based on specific dates in your Node.js applications using pg-promise with PostgreSQL. Happy querying!