error while converting the json column to text in PostgreSQL

I am trying to convert the json column to text

SELECT json_data->>'text' AS text
    FROM table1

it is giving below error

SQL Error [22P05]: ERROR: unsupported Unicode escape sequence Detail: \u0000 cannot be converted to text. Where: JSON data, line 2:   "j_description":...

I tried replacing the "\u0000" sequences with ''

SELECT regexp_replace(json_data, '\u0000', '', 'g')->>'text' AS text
    FROM table1 

it is giving below error

SQL Error [42883]: ERROR: function regexp_replace(json, unknown, unknown, unknown) does not exist

Hint: No function matches the given name and argument types. You might need to add explicit type casts.

I also tried with below script, but, no luck

 SELECT regexp_replace(json_data::text, '\u0000', '', 'g')->>'text' AS text
    FROM table1

 SELECT regexp_replace(cast(json_data as text, '\u0000', '', 'g')->>'text' AS text
    FROM table1

could someone advice me, please.

thank you

You are doing something wrong:

Just do:

SELECT json_data::text FROM table1

Instead of:

SELECT json_data->>'text' AS text
FROM table1

UPDATE:

The Select should look so:

SELECT json_data->>'j_description'::text as result from table1;

UPDATE:

SELECT regexp_replace(json_data::text, '\u0000', 'newOne')::json->>'j_description'::text as result from table1;

UPDATE:

Based on this kind of problem a good solution in my opinion contains 2 steps:

1. Do clean of all columns and replace \u0000 to something like.

    update table1
    set json_data = REPLACE(json_data::text, '\u0000', '' )::json 
    where json_data::text like '%\u0000%';
   

2.The select will work well without any regex_replace

SELECT json_data->>'j_description'::text as result from table1;

Finally you should do it for all columns that you need json_data here is for an example.