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JSON functions and operators

JSON functions

jsonb_array_elements

Expands the top-level JSON array into a set of JSON values.

Syntax
jsonb_array_elements ( jsonb ) → setof jsonb
Example
SELECT * FROM jsonb_array_elements('[1,true, [2,false]]'::jsonb);
------RESULT
1
true
[2, false]

jsonb_array_elements_text

Expands the top-level JSON array into a set of text (varchar) values.

Syntax
jsonb_array_elements_text ( jsonb ) → setof varchar
Example
SELECT * FROM jsonb_array_elements_text('["foo", "bar"]'::jsonb)
------RESULT
foo
bar

jsonb_array_length

Returns the number of elements in the top-level JSON array.

Syntax
jsonb_array_length ( jsonb ) → integer
Example
SELECT jsonb_array_length('[1,2,3,{"f1":1,"f2":[5,6]},4]');
------RESULT
5

jsonb_build_array

Builds a JSON array out of a variadic argument list. Each argument is converted as per to_jsonb.

Syntax
jsonb_build_array ( VARIADIC "any" ) → jsonb
Example
SELECT jsonb_build_array(1, 2, 'foo', 4, 5);
------RESULT
[1, 2, "foo", 4, 5]

jsonb_build_object

Builds a JSON object out of a variadic argument list. By convention, the argument list consists of alternating keys and values. Key arguments are coerced to text; value arguments are converted as per to_jsonb.

Syntax
jsonb_build_object ( VARIADIC "any" ) → jsonb
Example
SELECT jsonb_build_object('foo', 1, 2, row(3,'bar'));
------RESULT
{"2": {"f1": 3, "f2": "bar"}, "foo": 1}

jsonb_each

Expands the top-level JSON object into a set of key-value pairs.

Syntax
jsonb_each ( jsonb ) → setof record ( key varchar, value jsonb )
Example
SELECT * FROM jsonb_each('{"a":"foo", "b":"bar"}'::jsonb);
------RESULT
a "foo"
b "bar"

jsonb_each_text

Expands the top-level JSON object into a set of key-value pairs. The returned values will be of type varchar.

Syntax
jsonb_each_text ( jsonb ) → setof record ( key varchar, value varchar )
Example
SELECT * FROM jsonb_each_text('{"a":"foo", "b":"bar"}'::jsonb);
------RESULT
key | value
-----+-------
a | foo
b | bar

jsonb_extract_path

Extracts JSON sub-object at the specified path.

This function is equivalent to the #> operator in functionality.

Syntax
jsonb_extract_path ( from_json jsonb, VARIADIC path_elems text[] ) → jsonb
  • from_json is the input JSON value from which to extract the sub-object.

  • path_elems is the path elements that specify the location of the desired sub-object in the JSON structure. Multiple path elements can be provided as separate arguments.

Example
SELECT json_extract_path('{"f2":{"f3":1},"f4":{"f5":99,"f6":"foo"}}', 'f4', 'f6')
------RESULT
"foo"

jsonb_extract_path_text

Extracts JSON sub-object at the specified path as text.

This function is equivalent to the #>> operator in functionality.

Syntax
jsonb_extract_path_text ( from_json jsonb, VARIADIC path_elems text[] ) → text
Example
SELECT jsonb_extract_path_text('{"f2":{"f3":1},"f4":{"f5":99,"f6":"string"}}', 'f4', 'f6');
------RESULT
string

jsonb_object_keys

Returns the set of keys in the top-level JSON object.

Syntax
jsonb_object_keys ( jsonb ) → setof varchar
Example
SELECT * FROM jsonb_object_keys('{"f1":"abc","f2":{"f3":"a", "f4":"b"}}'::jsonb);
------RESULT
f1
f2

jsonb_strip_nulls

Removes all object fields that have null values from a given JSONB value, recursively. Empty objects or null values that are not object fields are left untouched.

Syntax
jsonb_strip_nulls ( jsonb ) → jsonb
Example
-- Handling non-null values
SELECT jsonb_strip_nulls('{"a": 1, "b": null, "c": {"d": null, "e": 2}}');
------RESULT
{"a": 1, "c": {"e": 2}}

-- Empty object preservation
SELECT jsonb_strip_nulls('{"a": {"b": null, "c": null}, "d": {} }');
------RESULT
{"a": {}, "d": {}}

jsonb_path_exists

Checks if a JSON path returns any items from a JSON value.

If the vars argument is provided, it must be a JSON object. Its fields act as named values that are substituted into the path expression. When the silent argument is specified and set to true, the function will suppress errors like the @? and @@ operators.

For information on the SQL/JSON Path syntax, refer to the PostgreSQL documentation.

Syntax
jsonb_path_exists ( target jsonb, path varchar [, vars jsonb [, silent boolean ]] ) → boolean
Example
SELECT jsonb_path_exists('{"a":1, "b":2, "c":3}', '$.b');
------RESULT
t

jsonb_path_match

Evaluates a JSON path predicate on a JSON value and returns the results as a boolean. Only the first item of the result is taken into account.

Syntax
jsonb_path_match ( target jsonb, path varchar [, vars jsonb [, silent boolean ]] ) → boolean
Example
SELECT jsonb_path_match('{"employee":{"name":"John","age":30}}', 'exists($.employee.age ? (@ > 25))');
------RESULT
t

jsonb_path_query

Extracts items from a JSON value matching a JSON path and returns as a set.

Syntax
jsonb_path_query ( target jsonb, path varchar [, vars jsonb [, silent boolean ]] ) → setof jsonb
Example
SELECT jsonb_path_query('{
"employees": [
{
"name": "John",
"age": 30
},
{
"name": "Jane",
"age": 25
},
{
"name": "David",
"age": 35
},
{
"name": "Michael",
"age": 32
}
]
}', '$.employees[*] ? (@.age >= 25 && @.age <= 30)');
------RESULT
jsonb_path_query
------------------------------
{"age": 30, "name": "John"}
{"age": 25, "name": "Jane"}

jsonb_path_query_array

Extracts matching JSON path items and returns them wrapped in an array.

Syntax
jsonb_path_query_array ( target jsonb, path varchar [, vars jsonb [, silent boolean ]] ) → jsonb
Example
SELECT jsonb_path_query_array('{
"employees": [
{
"name": "John",
"age": 30
},
{
"name": "Alice",
"age": 35
},
{
"name": "Bob",
"age": 25
}
]
}', '$.employees[*] ? (@.age >= $min && @.age <= $max)', '{"min": 24, "max": 32}');
------RESULT
jsonb_path_query_array
-----------------------------------------------------------
[{"age": 30, "name": "John"}, {"age": 25, "name": "Bob"}]

jsonb_path_query_first

Extracts the first matching item from a JSON value using a JSON path.

Syntax
jsonb_path_query_first ( target jsonb, path varchar [, vars jsonb [, silent boolean ]] ) → jsonb
Example
SELECT jsonb_path_query_first('{
"employees": [
{
"name": "John",
"age": 30
},
{
"name": "Jane",
"age": 25
},
{
"name": "David",
"age": 35
}
]
}', '$.employees[0]');
------RESULT
jsonb_path_query_first
-----------------------------
{"age": 30, "name": "John"}

jsonb_typeof

Returns the type of the top-level JSON value as a text string.

Syntax
jsonb_typeof ( jsonb ) → varchar
Example
SELECT jsonb_typeof ('-123.4');
------RESULT
number

jsonb_pretty

This function takes a jsonb value and returns a text representing the formatted, indented JSON value.

Syntax
jsonb_pretty ( jsonb JSONB )TEXT
Examples
SELECT jsonb_pretty('[{"f1":1,"f2":null}, 2]');
------RESULT
[
{
"f1": 1,
"f2": null
},
2
]

jsonb_object

This function takes an array of text elements and returns a jsonb object where adjacent pairs of values are taken as the key and value of an object property.

Syntax
jsonb_object ( text_array TEXT[] )JSONB
Examples
jsonb_object('{a, 1, b, def, c, 3.5}' :: text[]) → {"a": "1", "b": "def", "c": "3.5"}
jsonb_object(array['a', null]) → {"a": null}

to_jsonb

Converts any SQL value to JSONB data type. It recursively handles arrays and composites, transforming them into arrays and objects in the resulting JSON representation. If a direct cast from the SQL data type to JSON is available, it is used for the conversion; otherwise, scalar values are produced as JSON scalars, with text representations appropriately escaped to ensure valid JSON string values.

Syntax
to_jsonb ( any )JSONB
Examples
to_jsonb(array['apple', 'banana', 'cherry'])["apple", "banana", "cherry"]
to_jsonb('Products labeled "expired"'::string)"Products labeled \"expired\""

JSON operators

jsonb -> integer → jsonb

Extracts the n'th element of a JSON array (array elements are indexed from zero, but negative integers count from the end).

Example
SELECT'[{"a":"foo"},{"b":"bar"},{"c":"baz"}]'::jsonb -> 2;
------RESULT
{"c":"baz"}

jsonb -> varchar → jsonb

Extracts JSON object field with the given key.

Example
SELECT '{"a": {"b":"foo"}}'::jsonb -> 'a';
------RESULT
{"b": "foo"}

jsonb ->> integer → varchar

Extracts the n'th element of a JSON array, as text.

Example
SELECT '[1,2,3]'::jsonb ->> 2;
------RESULT
3

jsonb ->> varchar → varchar

Extracts JSON object field with the given key, as text.

Example
SELECT '{"a":1,"b":2}'::jsonb ->> 'b';
------RESULT
2

jsonb - text → jsonb

Deletes a key (and its value) from a JSON object, or matching string value(s) from a JSON array.

Examples
'{"a": "b", "c": "d"}'::jsonb - 'a'{"c": "d"}
'["a", "b", "c", "b"]'::jsonb - 'b'["a", "c"]

jsonb - text[] → jsonb

Deletes all matching keys or array elements from a JSON object.

Example
'{"a": "b", "c": "d"}'::jsonb - '{a,c}'::text[]{}

jsonb - integer → jsonb

Deletes the array element with the specified index (negative integers counting from the end). Throws an error if JSON object is not an array.

Example
'["a", "b"]'::jsonb - 1["a"]

jsonb #- text[] → jsonb

Deletes the field or array element at the specified path, where path elements can be either field keys or array indexes.

Example
'["a", {"b":1}]'::jsonb #- '{1,b}' → ["a", {}]

(jsonb || jsonb) → jsonb

Concatenates jsonb data.

Examples
SELECT '["a", "b"]'::jsonb || '["a", "d"]'::jsonb;  
SELECT '{"a": "b"}'::jsonb || '{"c": "d"}'::jsonb;
SELECT '[1, 2]'::jsonb || '3'::jsonb;
SELECT '{"a": "b"}'::jsonb || '42'::jsonb;
------RESULT
["a", "b", "a", "d"]
{"a": "b", "c": "d"}
[1, 2, 3]
[{"a": "b"}, 42]

jsonb @> jsonb → boolean

This operator checks if the left jsonb value contains the right jsonb value. For a detailed description and examples about containment and existence, see jsonb Containment and Existence in PostgreSQL's documentation.

Examples
'[1, 2, 3]'::jsonb @> '[1, 3]'::jsonb → t

'{"product": "PostgreSQL", "version": 9.4, "jsonb": true}'::jsonb @> '{"version": 9.4}'::jsonb → t

'{"foo": {"bar": "baz"}}'::jsonb @> '{"bar": "baz"}'::jsonb → f

'{"foo": {"bar": "baz"}}'::jsonb @> '{"foo": {}}'::jsonb → t

jsonb <@ jsonb → boolean

This operator checks if the left jsonb value is contained within the right jsonb value. For a detailed description and examples about containment and existence, see jsonb Containment and Existence in PostgreSQL's documentation.

Examples
'{"b":2}'::jsonb <@ '{"a":1, "b":2}'::jsonb → t

jsonb ? text → boolean

This operator checks if a string exists as a top-level array element or object key within a jsonb value.

Examples
'["foo", "bar", "baz"]'::jsonb ? 'bar' → t

'{"foo": "bar"}'::jsonb ? 'foo' → t

'{"foo": "bar"}'::jsonb ? 'bar' → f

'{"foo": {"bar": "baz"}}'::jsonb ? 'bar' → f

'"foo"'::jsonb ? 'foo' → t

jsonb ?| text[] → boolean

This operator checks if any string in an array exists as a top-level array element or object key within a jsonb value.

Examples
'{"a":1, "b":2, "c":3}'::jsonb ?| array['b', 'd']t

'["a", "b", "c"]'::jsonb ?| array['b', 'd']t

'"b"'::jsonb ?| array['b', 'd']t

json ?& text[] → boolean

This operator checks if all strings in an array exist as top-level array elements or object keys within a jsonb value.

Examples
'{"a":1, "b":2, "c":3}'::jsonb ?& array['a', 'b']t

'["a", "b", "c"]'::jsonb ?& array['a', 'b']t

'["a", "b", "c"]'::jsonb ?& array['a', 'd']f

jsonb #> text[] → jsonb

This operator extracts a nested value from a JSONB object using a text array of keys or indices.

Examples
'{"a": {"b": ["foo","bar"]}}'::jsonb #> '{a,b,1}'::text[] → "bar"

'{"a": {"b": ["foo","bar"]}}'::jsonb #> '{a,b,null}'::text[] → NULL

jsonb #>> text[] → text

This operator extracts a nested value as text from a JSONB object using a text array of keys or indices.

Examples
'{"a": {"b": ["foo","bar"]}}'::jsonb #>> '{a,b,1}'::text[] → bar

'{"a": {"b": ["foo",null]}}'::jsonb #>> '{a,b,1}'::text[] → NULL

'{"a": {"b": ["foo","bar"]}}'::jsonb #>> '{a,b,null}'::text[] → NULL

jsonb @? varchar → boolean

Determine whether the specified JSON path returns any item for the given JSON value.

Examples
SELECT '{"a":1, "b":2, "c":3}'::jsonb @? '$.a';
------RESULT
t

SELECT '{"a":1, "b":2, "c":3}'::jsonb @? '$.d';
------RESULT
f

jsonb @@ varchar → boolean

Returns the result of a JSON path predicate check on the specified JSON value, considering only the first item of the result. If the result is not a Boolean, it returns NULL.

Examples
SELECT '{"numbers":[1,2,3,4,5]}'::jsonb @@ '$.numbers[*] == 5';
------RESULT
t

IS JSON predicate

This predicate tests whether an expression can be parsed as JSON, optionally of a specified type. It evaluates the JSON structure and returns a boolean result indicating whether the value matches the specified JSON type.

Syntax
expression IS [ NOT ] JSON [ VALUE | ARRAY | OBJECT | SCALAR ]bool

If SCALAR, ARRAY, or OBJECT is specified, the test is whether or not the JSON is of that particular type.

Example
SELECT js,
js IS JSON "json?",
js IS JSON SCALAR "scalar?",
js IS JSON OBJECT "object?",
js IS JSON ARRAY "array?"
FROM (VALUES
('123'), ('"abc"'), ('{"a": "b"}'), ('[1,2]'),('abc')) foo(js);
Result

js | json? | scalar? | object? | array?
------------+-------+---------+---------+---------
123 | t | t | f | f
"abc" | t | t | f | f
{"a": "b"} | t | f | t | f
[1,2] | t | f | f | t
abc | f | f | f | f
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