Hi, community. I’ve submitted a PR for applying two different NULL semantics for CONCAT function, because this function now returns NULL when any of the arguments is NULL, however Postgresql and MSSQL have different behavior(they treat NULL as empty string). BTW, CONCAT enabled in Oracle(we call it CONCAT2 in Calcite) has been resolved in CALCITE-5745, if anyone needs to refer to.
https://github.com/apache/calcite/pull/3258 Best, ZheHu
