> With the hstore you can do hstore ? 'key' to check if the object contains
> the key-- is there a similar function for json objects?
Is this good enough?:
=> select ('{"a":1,"b":null}'::json) -> 'a';
?column?
----------
1
=> select ('{"a":1,"b":null}'::json) -> 'b';
?column?
----------
null
=> select ('{"a":1,"b":null}'::json) -> 'c';
?column?
----------
NULL
=> select (('{"a":1,"b":null}'::json) -> 'a') IS NULL;
?column?
----------
f
Time: 0.334 ms
=> select (('{"a":1,"b":null}'::json) -> 'b') IS NULL;
?column?
----------
f
=> select (('{"a":1,"b":null}'::json) -> 'c') IS NULL;
?column?
----------
t
If you want to treat {"b":null} and absence of "b" the same way you
can use ->> instead of ->.
This does seem worrisome though:
=> select (('{"a":1, "b":null}'::json) -> 'b')::text;
text
------
null
I think json_typeof solves that in 9.4, but I don't see anything in
9.3 other than ->>.
Paul
--
_________________________________
Pulchritudo splendor veritatis.