Wrong types for NULL values when inserting data into postgres db

[pawmot]

Instead of trying to explain the problem in details I have created a small project that shows it: https://github.com/pawmot/querydsl-bug-reproduction

In short: when having a table with a foreign key constraint (in my case to a dictionary table) and using subselect to get the Id of the dictionary row based on its value, then if there are INTEGER columns specified after the reference column that have null passed in values(...) call, then I get an exception similar to this: column "number2" is of type integer but expression is of type character varying.

In our project with get that exception on a SMALLINT column, here I was able to show the problem only on INTEGER column, I don't know exactly why. The problem can be circumvented by:
a) moving the reference column to the last position in columns(...) call.
b) using the populate(...) call.

If I'm doing something wrong, then please let me know, but I have tried to find something about this issue in documentation and I googled the problem without any success.

[stale]

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