Re: [GENERAL] How to stop array_to_json from interpolating columnnames that weren't there

​Are you referring to the fact that ​this provokes an error?

"select json_agg(*) from schemata;"

select schemata from schemata;

you get one column in the output, while:

select * from schemata

results in an output relation having three columns - the "*" expands the composite type in the FROM clause into its component columns in the select-list

json_agg(*) fails since it is not expecting 3 columns (though oddly the error I see in 9.6 indicates its actually looking for a 0-arity function... "function json_agg() does not exist" - which implies that generally one cannot place a * in a function call, even if it would result in a single column.  This may even be documented but I haven't the desire to look right now...)

David J.