SELECT '[]'::JSON;
 json 
------
 []
(1 row)

SELECT '['::JSON;
ERROR:  could not parse JSON value
LINE 1: SELECT '['::JSON;
               ^
SELECT '[1,2,3]'::JSON;
  json   
---------
 [1,2,3]
(1 row)

SELECT '[1,2,3]'::JSON::TEXT;
  text   
---------
 [1,2,3]
(1 row)

SELECT '[1,2,3  ]'::JSON;
   json    
-----------
 [1,2,3  ]
(1 row)

SELECT '[1,2,3  ,4]'::JSON;
    json     
-------------
 [1,2,3  ,4]
(1 row)

SELECT '[1,2,3  ,4.0]'::JSON;
     json      
---------------
 [1,2,3  ,4.0]
(1 row)

SELECT '[1,2,3  ,4]'::JSON;
    json     
-------------
 [1,2,3  ,4]
(1 row)

SELECT 'true'::JSON;
 json 
------
 true
(1 row)

SELECT 'true'::TEXT::JSON;
 json 
------
 true
(1 row)

SELECT 'false'::JSON;
 json  
-------
 false
(1 row)

SELECT 'null'::JSON;
 json 
------
 null
(1 row)

SELECT '1.1'::JSON;
 json 
------
 1.1
(1 row)

SELECT '"string"'::JSON;
   json   
----------
 "string"
(1 row)

SELECT '{"key1":"value1", "key2":"value2"}'::JSON;
                json                
------------------------------------
 {"key1":"value1", "key2":"value2"}
(1 row)

SELECT '{"key1":"value1", "key2":"value2"}'::JSON;
                json                
------------------------------------
 {"key1":"value1", "key2":"value2"}
(1 row)

SELECT 15::JSON;
 json 
------
 15
(1 row)

SELECT json_get_type('[]');
 json_get_type 
---------------
 array
(1 row)

SELECT json_get_type('{}');
 json_get_type 
---------------
 object
(1 row)

SELECT json_get_type('true');
 json_get_type 
---------------
 bool
(1 row)

SELECT json_get_type('false');
 json_get_type 
---------------
 bool
(1 row)

SELECT json_get_type('null');
 json_get_type 
---------------
 null
(1 row)

CREATE TABLE testjson (j JSON);
INSERT INTO testjson VALUES ('[1,2,3,4]');
INSERT INTO testjson VALUES ('{"key":"value"}');
INSERT INTO testjson VALUES ('{"key":"value"');
ERROR:  could not parse JSON value
LINE 1: INSERT INTO testjson VALUES ('{"key":"value"');
                                     ^
INSERT INTO testjson VALUES ('');
ERROR:  could not parse JSON value
LINE 1: INSERT INTO testjson VALUES ('');
                                     ^
INSERT INTO testjson VALUES ('""');
INSERT INTO testjson VALUES ('true');
INSERT INTO testjson VALUES ('false');
INSERT INTO testjson VALUES ('null');
INSERT INTO testjson VALUES ('[]');
INSERT INTO testjson VALUES ('{}');
SELECT * FROM testjson;
        j        
-----------------
 [1,2,3,4]
 {"key":"value"}
 ""
 true
 false
 null
 []
 {}
(8 rows)

SELECT json_get_type(j) FROM testjson;
 json_get_type 
---------------
 array
 object
 string
 bool
 bool
 null
 array
 object
(8 rows)

-- to_json: null
SELECT to_json(NULL);
ERROR:  could not determine polymorphic type because input has type "unknown"
SELECT to_json(NULL::INT);
 to_json 
---------
 null
(1 row)

SELECT to_json(NULL::INT[]);
 to_json 
---------
 null
(1 row)

SELECT to_json(NULL::VOID);
ERROR:  to_json cannot convert void to JSON
SELECT to_json(NULL::MONEY);
ERROR:  to_json cannot convert money to JSON
SELECT to_json('null'::text); -- should yield '"null"', not 'null'
 to_json 
---------
 "null"
(1 row)

SELECT json_get_type(to_json(NULL));
ERROR:  could not determine polymorphic type because input has type "unknown"
SELECT json_get_type(to_json(NULL::INT));
 json_get_type 
---------------
 null
(1 row)

SELECT json_get_type(to_json(NULL::VOID));
ERROR:  to_json cannot convert void to JSON
SELECT json_get_type(to_json(NULL::MONEY));
ERROR:  to_json cannot convert money to JSON
-- to_json: string
SELECT to_json('');
ERROR:  could not determine polymorphic type because input has type "unknown"
SELECT json_get_type(to_json(''));
ERROR:  could not determine polymorphic type because input has type "unknown"
SELECT to_json('string');
ERROR:  could not determine polymorphic type because input has type "unknown"
SELECT json_get_type(to_json('string'));
ERROR:  could not determine polymorphic type because input has type "unknown"
SELECT to_json('string'::VARCHAR);
 to_json  
----------
 "string"
(1 row)

SELECT json_get_type(to_json('string'::VARCHAR));
 json_get_type 
---------------
 string
(1 row)

SELECT to_json('string'::VARCHAR(3));
 to_json 
---------
 "str"
(1 row)

SELECT json_get_type(to_json('string'::VARCHAR(3)));
 json_get_type 
---------------
 string
(1 row)

SELECT to_json('{1,2,3}'::TEXT);
  to_json  
-----------
 "{1,2,3}"
(1 row)

SELECT json_get_type(to_json('{1,2,3}'::TEXT));
 json_get_type 
---------------
 string
(1 row)

SELECT to_json('"doubly-encoded"'::JSON);
       to_json        
----------------------
 "\"doubly-encoded\""
(1 row)

SELECT json_get_type(to_json('"doubly-encoded"'::JSON));
 json_get_type 
---------------
 string
(1 row)

SELECT to_json('"nested quotes"'::TEXT);
       to_json       
---------------------
 "\"nested quotes\""
(1 row)

SELECT json_get_type(to_json('"nested quotes"'::TEXT));
 json_get_type 
---------------
 string
(1 row)

SELECT to_json('"nested quotes"'::TEXT)::TEXT::JSON;
       to_json       
---------------------
 "\"nested quotes\""
(1 row)

SELECT json_get_type(to_json('"nested quotes"'::TEXT)::TEXT::JSON);
 json_get_type 
---------------
 string
(1 row)

SELECT to_json('h'::CHAR);
 to_json 
---------
 "h"
(1 row)

SELECT json_get_type(to_json('h'::CHAR));
 json_get_type 
---------------
 string
(1 row)

SELECT to_json('hello world'::CHAR);
 to_json 
---------
 "h"
(1 row)

SELECT json_get_type(to_json('hello world'::CHAR));
 json_get_type 
---------------
 string
(1 row)

SELECT to_json('hello world!'::CHAR(11));
    to_json    
---------------
 "hello world"
(1 row)

SELECT json_get_type(to_json('hello world!'::CHAR(11)));
 json_get_type 
---------------
 string
(1 row)

-- to_json: number
SELECT to_json(12345);
 to_json 
---------
 12345
(1 row)

SELECT to_json(12345.678);
  to_json  
-----------
 12345.678
(1 row)

SELECT json_get_type(to_json(12345));
 json_get_type 
---------------
 number
(1 row)

SELECT json_get_type(to_json(12345.678));
 json_get_type 
---------------
 number
(1 row)

SELECT to_json(+1.23e100::FLOAT);
  to_json  
-----------
 1.23e+100
(1 row)

SELECT to_json('+1.23e100'::FLOAT);
  to_json  
-----------
 1.23e+100
(1 row)

SELECT to_json(123456789012345678901234567890123456789012345678901234567890.123456789012345678901234567890123456789012345678901234567890);
                                                          to_json                                                          
---------------------------------------------------------------------------------------------------------------------------
 123456789012345678901234567890123456789012345678901234567890.123456789012345678901234567890123456789012345678901234567890
(1 row)

SELECT json_get_type(to_json(123456789012345678901234567890123456789012345678901234567890.123456789012345678901234567890123456789012345678901234567890));
 json_get_type 
---------------
 number
(1 row)

SELECT to_json('100'::MONEY);
ERROR:  to_json cannot convert money to JSON
-- to_json: bool
SELECT to_json(TRUE);
 to_json 
---------
 true
(1 row)

SELECT to_json(FALSE);
 to_json 
---------
 false
(1 row)

SELECT to_json(1=1);
 to_json 
---------
 true
(1 row)

SELECT to_json(1=2);
 to_json 
---------
 false
(1 row)

SELECT json_get_type(to_json(TRUE));
 json_get_type 
---------------
 bool
(1 row)

SELECT json_get_type(to_json(FALSE));
 json_get_type 
---------------
 bool
(1 row)

SELECT json_get_type(to_json(1=1));
 json_get_type 
---------------
 bool
(1 row)

SELECT json_get_type(to_json(1=2));
 json_get_type 
---------------
 bool
(1 row)

SELECT to_json(TRUE::TEXT)::TEXT = '"' || TRUE || '"';
 ?column? 
----------
 t
(1 row)

SELECT to_json(FALSE::TEXT)::TEXT = '"' || FALSE || '"';
 ?column? 
----------
 t
(1 row)

-- to_json: array
SELECT to_json(ARRAY[1,2,3]);
 to_json 
---------
 [1,2,3]
(1 row)

-- more tests are in array_to_json.sql
-- to_json: invalid types
SELECT to_json(row(1,2));
ERROR:  to_json cannot convert record to JSON
SELECT to_json('127.0.0.1'::INET);
ERROR:  to_json cannot convert inet to JSON
-- from_json: null
SELECT from_json(null);
 from_json 
-----------
 
(1 row)

SELECT from_json(NULL::TEXT);
ERROR:  function from_json(text) does not exist
LINE 1: SELECT from_json(NULL::TEXT);
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
SELECT from_json(NULL::JSON);
 from_json 
-----------
 
(1 row)

-- from_json: string
SELECT from_json('"valid string"');
  from_json   
--------------
 valid string
(1 row)

-- Use unaligned output so results are consistent between PostgreSQL 8 and 9.
\a
SELECT from_json($$ "hello\nworld" $$);
from_json
hello
world
(1 row)
\a
SELECT from_json($$ "hello\u0000world" $$);
ERROR:  could not convert JSON-encoded string to TEXT: contains \u0000
DETAIL:  the string was:  "hello\u0000world" 
-- from_json: number
SELECT from_json('123');
 from_json 
-----------
 123
(1 row)

SELECT from_json('123')::INT;
 from_json 
-----------
       123
(1 row)

SELECT from_json('123.456')::INT;
ERROR:  invalid input syntax for integer: "123.456"
SELECT from_json('123.456')::FLOAT;
 from_json 
-----------
   123.456
(1 row)

SELECT from_json('123e-38');
 from_json 
-----------
 123e-38
(1 row)

SELECT from_json('123e-38')::FLOAT;
 from_json 
-----------
  1.23e-36
(1 row)

SELECT from_json('1.23e-38')::FLOAT;
 from_json 
-----------
  1.23e-38
(1 row)

SELECT from_json('1.23e-38');
 from_json 
-----------
 1.23e-38
(1 row)

SELECT from_json('1.23e-38')::NUMERIC;
                 from_json                  
--------------------------------------------
 0.0000000000000000000000000000000000000123
(1 row)

-- from_json: bool
SELECT from_json('true')::JSON;
 from_json 
-----------
 true
(1 row)

SELECT from_json('true');
 from_json 
-----------
 true
(1 row)

SELECT from_json('true')::BOOLEAN;
 from_json 
-----------
 t
(1 row)

SELECT from_json('true')::BOOLEAN::JSON;
ERROR:  could not parse JSON value
SELECT from_json('true')::BOOLEAN::TEXT::JSON;
 from_json 
-----------
 true
(1 row)

SELECT from_json('false')::BOOLEAN::TEXT::JSON;
 from_json 
-----------
 false
(1 row)

SELECT from_json('false');
 from_json 
-----------
 false
(1 row)

SELECT from_json('f');
ERROR:  could not parse JSON value
LINE 1: SELECT from_json('f');
                         ^
SELECT from_json('t');
ERROR:  could not parse JSON value
LINE 1: SELECT from_json('t');
                         ^
SELECT from_json('f'::BOOLEAN::TEXT);
ERROR:  function from_json(text) does not exist
LINE 1: SELECT from_json('f'::BOOLEAN::TEXT);
               ^
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.
SELECT from_json('f'::BOOLEAN::TEXT::JSON);
 from_json 
-----------
 false
(1 row)

SELECT from_json('t'::BOOLEAN::TEXT::JSON);
 from_json 
-----------
 true
(1 row)

-- from_json: object
SELECT from_json('{"key": "value"}');
ERROR:  from_json cannot be applied to JSON objects
-- from_json: array
SELECT from_json('[1,2,3]');
ERROR:  from_json cannot be applied to JSON arrays
-- from_json: invalid
SELECT from_json('invalid');
ERROR:  could not parse JSON value
LINE 1: SELECT from_json('invalid');
                         ^
CREATE TABLE sample_query_text (json JSON);
INSERT INTO sample_query_text VALUES ($$
"SELECT pg_catalog.quote_ident(c.relname) FROM pg_catalog.pg_class c WHERE c.relkind IN ('i') AND substring(pg_catalog.quote_ident(c.relname),1,0)='' AND pg_catalog.pg_table_is_visible(c.oid) AND c.relnamespace <> (SELECT oid FROM pg_catalog.pg_namespace WHERE nspname = 'pg_catalog')\nUNION\nSELECT pg_catalog.quote_ident(n.nspname) || '.' FROM pg_catalog.pg_namespace n WHERE substring(pg_catalog.quote_ident(n.nspname) || '.',1,0)='' AND (SELECT pg_catalog.count(*) FROM pg_catalog.pg_namespace WHERE substring(pg_catalog.quote_ident(nspname) || '.',1,0) = substring('',1,pg_catalog.length(pg_catalog.quote_ident(nspname))+1)) > 1\nUNION\nSELECT pg_catalog.quote_ident(n.nspname) || '.' || pg_catalog.quote_ident(c.relname) FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n WHERE c.relnamespace = n.oid AND c.relkind IN ('i') AND substring(pg_catalog.quote_ident(n.nspname) || '.' || pg_catalog.quote_ident(c.relname),1,0)='' AND substring(pg_catalog.quote_ident(n.nspname) || '.',1,0) = substring('',1,pg_catalog.length(pg_catalog.quote_ident(n.nspname))+1) AND (SELECT pg_catalog.count(*) FROM pg_catalog.pg_namespace WHERE substring(pg_catalog.quote_ident(nspname) || '.',1,0) = substring('',1,pg_catalog.length(pg_catalog.quote_ident(nspname))+1)) = 1\n UNION SELECT 'ON' UNION SELECT 'CONCURRENTLY'\nLIMIT 1000"
$$);
SELECT md5(from_json(json)) FROM sample_query_text;
               md5                
----------------------------------
 1c0d28af72da21149acbdf305c197141
(1 row)