Postgres jsonb 'NOT contains' operator

Question

I'm experimenting with postgres jsonb column types, and so far so good. One common query I'm using is like this:

select count(*) from jsonbtest WHERE attributes @> '{"City":"Mesa"}';

How do I reverse that? Is there a different operator or is it simply used as

select count(*) from jsonbtest WHERE NOT attributes @> '{"City":"Mesa"}';

Solution 1

Two way, you can test any json(b) value

• the ->> operator extract value as text. But this operation slow, if you will use the value only test
• the @> operator test any json(b) contain any json(b). This is a quick but you are not tested NOT option.

Simply and quick way:

NOT (attribute @> '{"City":"Mesa"}'::jsonb)

I've change attribute->>'City' <> 'Mesa' to NOT (attribute @> '{"City":"Mesa"}'::jsonb) and my ~2.000.000 rows query result time changed 45secs to 25secs.

Solution 2

This can be achieved with several conditions. It's not elegant but I didn't find another way to do so.

So, first, get every row which simple don't have 'City' attribute and then add 'OR' condition to check for correct field value.

select count(*) from jsonbtest where 
  NOT(attributes ? 'City') 
  OR (attributes ? 'City') is NULL -- this is required if attributes can be null
  OR (attributes->>'City' != 'Mesa')) 

Comments

[redneb]

No, there is no dedicated operator for that. What's wrong with NOT?

[pozs]

@eykanal NOT works pretty well.

[drice304]

That would be the same as select count(*) from jsonbtest WHERE '{"City":"Mesa"}' @> attributes;, checking if {"City": "Mesa"} contains attributes which is not the same.

[A-Diddy]

This helped me a lot... I couldn't find anyting about on this use case on the PgSQL site. Thanks!