cheatsheets/_drafts/postgresql-json.md

title	category
Postgresql JSON	Development

SELECT * FROM users WHERE data->>'name' = 'John'
SELECT data->>'name' AS name FROM users

Operator	Example	Description	Returns
->	data->2	Get array element 2	JSON
->	data->'name'	Get object key name	JSON
#>	data#>'{a,b}'	Get keypath a,b (eg, data.a.b)	JSON
----	----	----	----
->>	data->>2	Get array element 2	text
->>	data->>'name'	Get object key name	text
#>	data#>>'{a,b}'	Get keypath a,b (eg, data.a.b)	text

> returns JSON, >> returns text.

Boolean operators

Operator	Example	Description
?	data ? 'name'	Does data have key name?
`?	`	`data ?
?&	data ?& array['a','b']	Does data have a and b?
@>	'{"a":1,"b":2}'::jsonb @> '{"b":2}'::jsonb	Does left include right?
<@	'{"a":1}'::jsonb <@ '{"a":1,"b":2}'::jsonb	Does right include left?

When ?/?|/?& works on objects, it checks keys; when it works on arrays, it checks for elements.

• '{"a":1}'::jsonb ? 'a'
• '["a"]'::jsonb ? 'a'

References

• https://www.postgresql.org/docs/9.4/static/functions-json.html
• https://www.postgresql.org/docs/9.4/static/datatype-json.html