Teodor Sigaev <teodor(at)sigaev(dot)ru> writes:
>> I think Teodor's solution is wrong as it stands, because if the subquery
>> finds matches for mapcfg and maptokentype, but none of those rows
>> produce a non-null ts_lexize result, it will instead emit one row with a
>> null result, which is not what should happen.
> But concatenation with NULL will have result NULL, so "Lexized token" column
> will have NULL as supposed.
Ah, you're right --- objection withdrawn.
regards, tom lane