In PostgreSQL 9.3 Beta 2 (?), how do I create an index on a JSON field? I tried it using the ->
operator used for hstore
but got the following error:
CREATE TABLE publishers(id INT, info JSON);
CREATE INDEX ON publishers((info->'name'));
ERROR: data type json has no default operator class for access method "btree" HINT: You must specify an operator class for the index or define a default operator class for the data type.
Found:
CREATE TABLE publishers(id INT, info JSON);
CREATE INDEX ON publishers((info->>'name'));
As stated in the comments, the subtle difference here is ->>
instead of ->
. The former one returns the value as text, the latter as a JSON object.