I see what you're saying there. The different from Hive isn't deliberate, but I believe this only happens in the very special case when all of the values in the CASE are NULL, without any cast. If any of them have a type, the query will execute. E.g. the below query runs and returns NULL. select 1 * (CASE WHEN '1' IS NULL THEN NULL ELSE cast(NULL as integer) END); Interestingly postgres behaves the same way as Impala psql (9.5.17, server 9.4.8)
Type "help" for help.
postgres=# select 1 * (CASE WHEN '1' IS NULL THEN NULL ELSE NULL END);
ERROR: operator does not exist: integer * text
LINE 1: select 1 * (CASE WHEN '1' IS NULL THEN NULL ELSE NULL END);
^
HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
postgres=# select 1 * (NULL);
?column?
----------
(1 row)
postgres=# select 1 * (NULL);
?column?
----------
(1 row) We could probably file a bug if this is causing issues for you, there no specific reason it shouldn't work that I know of.
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