While it’s true that DuckDB has a list_sort() function that allows us to sort lists, it’s also true that there’s a list_reverse_sort() function that sorts lists in reverse order.
Tag: lists
Using LIST_REVERSE() to Reverse the Items in a List in DuckDB
Deep amongst DuckDB’s vast selection of list functions lies the list_reverse() function. This function reverses the elements in a list. We simply pass the list to the function and it reverses the order of the elements in that list.
Not to be confused with the list_sort() or list_reverse_sort() functions, the list_reverse() function reverses the order of the items as they currently sit in the list. The ...sort() functions on the other hand, actually perform a sort operation on the list items.
A Look at DuckDB’s LIST_SORT() Function
DuckDB has a list_sort() function that does exactly what its name promises; sorts lists.
While the easiest way to use this function is to simply pass a list, we can also pass other arguments to fine-tune the results.
Continue readingRemoving Duplicates from a List in DuckDB with the LIST_DISTINCT() Function
DuckDB has a function called list_distinct() that enables us to remove duplicate values from a list. Any value that appears more than once is “deduped” and is returned once in the resulting list.
The function also removes any NULL values.
Continue reading4 Functions That Check Whether a List Contains a Given Value in DuckDB
When working with DuckDB, we may need to determine whether a specific value exists within a list or array. Fortunately, DuckDB offers four synonymous functions that enable us to accomplish this.
Continue readingUnnesting Lists & Structs with DuckDB’s UNNEST() Function
DuckDB has an unnest() function that we can use to unnest lists and structs. Well, it can also be applied to NULL, but that’ll return an empty result.
By “unnest” I mean it takes the list or struct, and it returns its contents as rows in a table. You might say that it converts lists and structs into tables, where each item in the list or struct becomes a row in the table.
Below are examples of using DuckDB’s unnest() function to unnest lists and structs.
Fix ‘Binder Error: ‘list_has_all’ cannot compare lists of different types’ in DuckDB
If you’re getting an error that reads “Binder Error: ‘list_has_all’ cannot compare lists of different types” in DuckDB, it appears that you’re passing two different types of lists to the list_has_all() function.
DuckDB’s list_has_all() function accepts two lists as arguments. These need to be of the same type.
To fix this issue, make sure that both lists are of the same type.
Continue readingCheck if a Sub-List Appears in a Larger List in DuckDB: LIST_HAS_ALL()
When working with lists in DuckDB, we sometimes need to check whether a list contains specific elements. The list_has_all() function is a handy tool that allows us to verify if all elements of one list exist within another. This function is particularly useful in filtering queries, data validation, and advanced list-based operations.
In this article, we’ll explore how list_has_all() works in DuckDB.
Flattening Nested Lists with DuckDB’s FLATTEN() Function
DuckDB has a flatten() function that we can use to flatten nested lists. The function concatenates a list of lists into a single list. So whether the outer list contains just one list or multiple lists, we can use the flatten() function to flatten them into one list.
However, it only goes one level deep, so that’s something to keep in mind.
Continue reading5 Functions that Concatenate Lists in DuckDB
DuckDB provides us with a bunch of list concatenation functions that do exactly the same thing; concatenate two lists. Actually, they’re all synonyms and so they can all be used interchangeably. There’s also a more general concatenation function that can also be used on lists.
So this article presents five functions that we can use to concatenate lists.
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