Postgres column with string unicode values - json

Question

i have a column query_params with type TEXT but the values are stored as a string unicode. each value in the column is prefixed with a u and i'm struggling to remove it
Is there a way to remove the u from the values and convert the values dictionary to columns?
for example, the query SELECT query_params FROM api_log LIMIT 2 returns two rows
{
u'state': u'CA',
u'page_size': u'1000',
u'market': u'Western',
u'requested_at': u'2014-10-28T00:00:00+00:00'
},
{
u'state': u'NY',
u'page_size': u'1000',
u'market': u'Eastern',
u'requested_at': u'2014-10-28T00:10:00+00:00'
}
is it possible to handle unicode in postgres and convert to columns:
state | page_size | market | requested_at
------+-----------+----------+---------------------------
CA | 1000 | Western | 2014-10-28T00:00:00+00:00
NY | 1000 | Eastern | 2014-10-28T00:10:00+00:00
Thanks for any help.

Answer 1

You should remove u letters and replace single quotes with double ones to get properly formatted json. Then you can use the ->> operator to get its attributes:
select
v->>'state' as state,
v->>'page_size' as page_size,
v->>'market' as market,
v->>'requested_at' as requested_at
from (
select regexp_replace(query_params, 'u\''([^\'']*)\''', '"\1"', 'g')::json as v
from api_log
) s;
Test the solution in SqlFiddle.
Read about POSIX Regular Expression in the documentation.
Find an explanation of the regexp expression in regex101.com.