How do I return a jsonb array and array of objects from my data?

Question

I have the following table:

CREATE TABLE mytable (
  id       serial PRIMARY KEY
, employee text UNIQUE NOT NULL
, data     jsonb
);

With t

Answer 1

You treat the result of the first join as JSON, not as text string, so use jsonb_each() instead of jsonb_each_text():

SELECT t.employee, json_object_agg(a.k, d.value) AS sales
FROM   mytable t
JOIN   LATERAL jsonb_each(t.data) a(k,v) ON a.k LIKE 'sales_%'
JOIN   LATERAL jsonb_to_recordset(a.v) d(yr text, value float) ON d.yr = '2012'
WHERE  t.employee = 'Jim'  -- works because employee is unique
GROUP  BY 1;

GROUP BY 1 is shorthand for GROUP BY t.employee.
Result:

employee | sales
---------+--------
Jim      | '{ "sales_tv" : 40, "sales_radio" : 76 }'

I also untangled and simplified your query.

json_object_agg() is instrumental in aggregating name/value pairs as JSON object. Optionally cast to jsonb if you need that - or use jsonb_object_agg() in Postgres 9.5 or later.

Using explicit JOIN syntax to attach conditions in their most obvious place.
The same without explicit JOIN syntax:

SELECT t.employee, json_object_agg(a.k, d.value) AS sales
FROM   mytable t
     , jsonb_each(t.data)      a(k,v) 
     , jsonb_to_recordset(a.v) d(yr text, value float)
WHERE  t.employee = 'Jim'
AND    a.k LIKE 'sales_%'
AND    d.yr = '2012'
GROUP  BY 1;