DBMS – Page 32

How ARG_MAX_NULL() Works in DuckDB

March 18, 2025 by Ian

In DuckDB, the arg_max_null() function works in a similar way to the arg_max() function, in that it finds the row with the maximum value in one column and returns the corresponding value from another column at that row.

But where it differs from arg_max() is in the way it deals with NULL values. Also, arg_max_null() only accepts two arguments, whereas arg_max() accepts an optional third argument. Additionally, there aren’t any aliases for arg_max_null() at the time of writing (arg_max() has a couple of aliases).

In this article we’ll look at how arg_max_null() works, and we’ll compare it with arg_max() to see how each function handles NULL values.

2 Ways to Add Years to a Date in DuckDB

May 7, 2025March 17, 2025 by Ian

DuckDB provides us with an easy way to add one or more time intervals to date values. This includes adding one or more years to a date.

Here are two options for adding one or more years to a date in DuckDB.

Fix “Not implemented Error: Unknown TimeZone” in DuckDB

March 16, 2025 by Ian

If you’re getting an error that reads “Not implemented Error: Unknown TimeZone” in DuckDB, it appears that you’re using an unknown timezone when specifying a timezone for a timestamp value.

To fix this issue, be sure to use a supported timezone.

Getting a List of Time Zones in DuckDB

March 15, 2025 by Ian

Sometimes we need to specify a time zone when constructing timestamp values in DuckDB. But we may not always know the exact value to use for the time zone.

Fortunately, we can use the pg_timezone_names() table function to get a list of available timezones in DuckDB.

SQLite Math Functions

March 14, 2025 by Ian

The following table outlines the inbuilt mathematical functions available in SQLite.

A Quick Overview of DuckDB’s LAST() Function

March 14, 2025 by Ian

DuckDB is an in-process SQL OLAP database management system designed for analytical workloads. Among its many functions is one called last(). This function returns the last value in a column.

Let’s take a look at the last() function in DuckDB.

The Difference Between AGE() and DATE_DIFF() in DuckDB

March 13, 2025 by Ian

Both AGE() and DATE_DIFF() are DuckDB functions used to calculate time differences, but they serve distinct purposes and exhibit different behaviors that are important to understand when working with temporal data.

This article explores the difference between these two functions.

Using MAKE_DATE() to Construct a Date in DuckDB

May 7, 2025March 12, 2025 by Ian

In DuckDB, the make_date() function enables us to create date values from individual year, month, and day components. This function is particularly useful when working with data that stores date components separately or when constructing date values programmatically.

4 Functions that Get the Week From a Date in DuckDB

April 14, 2025March 11, 2025 by Ian

Working with dates often requires extracting specific components, such as the week number, for analysis or reporting. In DuckDB, there are multiple functions to retrieve the week from a date, each catering to different needs. This article explores four such functions, including how to calculate the ISO week—a standard defined by ISO-8601 where weeks start on Monday and the first week of the year contains the year’s first Thursday.

MAX_BY() Examples in DuckDB

March 11, 2025 by Ian

DuckDB has a max_by() function that finds the row with the maximum value in one column and returns the corresponding value from another column at that row.

Below are some examples that demonstrate how it works.