You’re a legend, thank you so much, I was looking on the internal functions docs page, not that one!
John Sent from my iPhone On 13 Jun 2022, at 13:21, Martijn Visser <martijnvis...@apache.org> wrote: Hi John, You're mentioning that Flink doesn't support UNNEST, but it does [1]. Would this work for you? Best regards, Martijn [1] https://nightlies.apache.org/flink/flink-docs-release-1.15/docs/dev/table/sql/queries/joins/#array-expansion Op ma 13 jun. 2022 om 13:55 schreef John Tipper <john_tip...@hotmail.com<mailto:john_tip...@hotmail.com>>: Hi all, Flink doesn’t support the unnest() function, which takes an array and creates a row for each element in the array. I have column containing an array of map<str, str> and I’d like to implement my own unnest. I try this as an initial do-nothing implementation: @udtf(result_types=Datatypes.MAP( key_type=Datatypes.STRING(), value_type=Datatypes.STRING())) def my_unnest(arr): return [] I get an error when Flink starts: No match found for function signature my_unnest(<VARCHAR(2147483647), VARCHAR(2147483647)) MAP ARRAY>) Is there something that I’m missing in my definition please? Many thanks, John
