create schema test_json_quote;
set current_schema to 'test_json_quote';
select json_quote(E'a\tb');
 json_quote 
------------
 "a\tb"
(1 row)

select json_quote('a    b');
 json_quote 
------------
 "a    b"
(1 row)

select json_quote('"ab"');
 json_quote 
------------
 "\"ab\""
(1 row)

select json_quote('a
b');
 json_quote 
------------
 "a\nb"
(1 row)

select json_quote(null);
 json_quote 
------------
 
(1 row)

select json_quote(E'\'ab\'');
 json_quote 
------------
 "'ab'"
(1 row)

select json_quote(''ab'');
ERROR:  syntax error at or near "ab"
LINE 1: select json_quote(''ab'');
                            ^
select json_quote('\"ab\"');
  json_quote  
--------------
 "\\\"ab\\\""
(1 row)

select json_quote('');
 json_quote 
------------
 ""
(1 row)

select json_quote(ab);
ERROR:  column "ab" does not exist
LINE 1: select json_quote(ab);
                          ^
CONTEXT:  referenced column: json_quote
select json_quote('~!ada221');
 json_quote 
------------
 "~!ada221"
(1 row)

select json_quote('null');
 json_quote 
------------
 "null"
(1 row)

create table student(name VARCHAR(20) PRIMARY KEY);
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "student_pkey" for table "student"
insert into student (name) value(json_quote('lc'));
select name from student;
 name 
------
 "lc"
(1 row)

drop table student;
drop schema test_json_quote cascade;
reset current_schema;