Postgres perform regex query on jsonb field - sql

Question

I have a column in my Postgres database that stores jsonb type values. Some of these values are raw strings (not a list or dictionary). I want to be able to perform a regex search on this column, such as
select * from database where jsonb_column::text ~ regex_expression.
The issue is that for values that are already strings, converting from jsonb to text adds additional escaped double quotes at the beginning and end of the value. I don't want these included in the regex query. I understand why Postgres does this, but if, say we assume all values stored in the jsonb field were jsonb strings, is there a work around? I know you can use ->> to get a value out of a jsonb dictionary, but can't figure out a solution for just jsonb strings on their own.
Once I figure out how to make this query in normal Postgres, I want to translate it into Peewee. However, any and all help with even just the initial query would be appreciated!

Answer 1

Just cast the json to text. Here is an example:
class Reg(Model):
key = CharField()
data = BinaryJSONField()
class Meta:
database = db
for i in range(10):
Reg.create(key='k%s' % i, data={'k%s' % i: 'v%s' % i})
# Find the row that contains the json string "k1": "v1".
expr = Reg.data.cast('text').regexp('"k1": "v1"')
query = Reg.select().where(expr)
for row in query:
print(row.key, row.data)
Prints
k1 {'k1': 'v1'}

Answer 2

To extract a plain string (string primitive without key name) from a JSON value (json or jsonb), you can extract the "empty path" like:
SELECT jsonb '"my string"' #>> '{}';
This also works for me (with jsonb but not with json), but it's more of a hack:
SELECT jsonb '"my string"' ->> 0
So:
SELECT * FROM tbl WHERE (jsonb_column #>> '{}') ~ 'my regex here';