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MDEV-13594 (was MDEV-18530): Implement -> and ->> JSON path operators #4711

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MDEV-18530: Implement -> and ->> JSON path operators
kjarir Mar 4, 2026
d23fecd
Merge branch 'main' into mdev-18530-json-operators
kjarir Mar 6, 2026
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315 changes: 315 additions & 0 deletions mysql-test/main/json_operators.result
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#
# MDEV-13594: Support for -> and ->> JSON operators
#
# 1. Basic Extraction with ->
SELECT '{"a": 1, "b": "text"}'->'$.a' AS int_val,
'{"a": 1, "b": "text"}'->'$.b' AS str_val;
int_val str_val
1 "text"
# 2. Unquoted Extraction with ->>
SELECT '{"a": 1, "b": "text"}'->> '$.a' AS int_val,
'{"a": 1, "b": "text"}'->> '$.b' AS str_val;
int_val str_val
1 text
# 3. Chaining Operators
# Should support nested extraction
SELECT '{"a": {"b": {"c": 42}}}'->'$.a'->'$.b'->'$.c' AS chained_arrow,
'{"a": {"b": {"c": 42}}}'->'$.a'->'$.b'->>'$.c' AS chained_unquoted;
chained_arrow chained_unquoted
42 42
# 4. Operator Precedence
# -> and ->> bind tighter than arithmetic operators
SELECT '{"a": 5}'->'$.a' + 1 AS arrow_plus_one;
arrow_plus_one
6
SELECT '{"a": 5}'->> '$.a' + 1 AS unquoted_arrow_plus_one;
unquoted_arrow_plus_one
6
SELECT '{"a": 5}'->'$.a' * 2 AS arrow_times_two;
arrow_times_two
10
# 5. Table Integration
CREATE TABLE t1 (
id INT PRIMARY KEY,
data JSON
);
INSERT INTO t1 VALUES
(1, '{"name": "Alice", "meta": {"age": 25, "city": "London"}}'),
(2, '{"name": "Bob", "meta": {"age": 30, "city": "Paris"}}'),
(3, '{"name": "Charlie", "meta": null}');
# Usage in SELECT list
SELECT id, data->'$.name', data->>'$.meta.city' FROM t1;
id data->'$.name' data->>'$.meta.city'
1 "Alice" London
2 "Bob" Paris
3 "Charlie" NULL
# Usage in WHERE clause
SELECT data->>'$.name' FROM t1 WHERE data->'$.meta.age' > 25;
data->>'$.name'
Bob
# Usage in ORDER BY
SELECT data->>'$.name' FROM t1 ORDER BY data->'$.meta.age' DESC;
data->>'$.name'
Bob
Alice
Charlie
DROP TABLE t1;
# 6. Edge Cases: Invalid JSON and Paths
# Invalid JSON text returns a warning; result is NULL
SELECT '{"a": 1'->'$.a';
'{"a": 1'->'$.a'
NULL
Warnings:
Warning 4037 Unexpected end of JSON text in argument 1 to function 'json_extract'
# Missing key returns NULL (no error)
SELECT '{"a": 1}'->'$.no_key';
'{"a": 1}'->'$.no_key'
NULL
# Invalid path returns a warning; result is NULL
SELECT '{"a": 1}'->'invalid_path';
'{"a": 1}'->'invalid_path'
NULL
Warnings:
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
# 7. Integration with Generated Columns
CREATE TABLE t2 (
j JSON,
name VARCHAR(50) AS (j->>'$.name') VIRTUAL,
INDEX (name)
);
INSERT INTO t2 (j) VALUES ('{"name": "Zoe", "score": 100}');
SELECT name FROM t2;
name
Zoe
EXPLAIN SELECT name FROM t2 WHERE name = 'Zoe';
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 system name NULL NULL NULL 1
DROP TABLE t2;
# 8. Chaining with non-JSON results
# ->> returns a string. If the string is valid JSON, another -> can follow.
SELECT '{"outer": "{\\"inner\\": 1}"}'->> '$.outer'->'$.inner' AS complex_chain;
complex_chain
1
#
# 9. Ported tests from MySQL (Oracle). Authors at Oracle Corporation.
# Path: mysql-test/suite/json/inc/json_functions.inc
#
CREATE TABLE t1_mysql(autopk int primary key auto_increment, f1 JSON);
INSERT INTO t1_mysql(f1) VALUES
('{"a":1}'),
('{"a":3}'),
('{"a":2}'),
('{"a":11, "b":3}'),
('{"a":33, "b":1}'),
('{"a":22,"b":2}');
ANALYZE TABLE t1_mysql;
Table Op Msg_type Msg_text
test.t1_mysql analyze status Engine-independent statistics collected
test.t1_mysql analyze Warning Engine-independent statistics are not collected for column 'f1'
test.t1_mysql analyze status OK
SELECT f1->"$.a" FROM t1_mysql order by autopk;
f1->"$.a"
1
3
2
11
33
22
EXPLAIN SELECT f1->"$.a" FROM t1_mysql order by autopk;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1_mysql ALL NULL NULL NULL NULL 6 Using filesort
SELECT f1->"$.a" FROM t1_mysql WHERE f1->"$.b" > 1 order by autopk;
f1->"$.a"
11
22
EXPLAIN SELECT f1->"$.a" FROM t1_mysql WHERE f1->"$.b" > 1 order by autopk;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1_mysql ALL NULL NULL NULL NULL 6 Using where; Using filesort
SELECT f1->"$.a", f1->"$.b" FROM t1_mysql ORDER BY autopk;
f1->"$.a" f1->"$.b"
1 NULL
3 NULL
2 NULL
11 3
33 1
22 2
SELECT MAX(f1->"$.a"), f1->"$.b" FROM t1_mysql GROUP BY f1->"$.b";
MAX(f1->"$.a") f1->"$.b"
11 3
22 2
3 NULL
33 1
SELECT JSON_OBJECT("c",f1->"$.b") AS f2
FROM t1_mysql HAVING JSON_TYPE(f2->"$.c") <> 'NULL' ORDER BY autopk;
f2
{"c": 3}
{"c": 1}
{"c": 2}
Test unquoting operator
INSERT INTO t1_mysql(f1) VALUES
('{"t":"a"}'),
('{"t":"b"}'),
('{"t":"c"}');
Returned values should be quoted
SELECT f1->"$.t" FROM t1_mysql WHERE f1->"$.t" <> 'NULL' order by autopk;
f1->"$.t"
"a"
"b"
"c"
Returned values should be unquoted
SELECT f1->>"$.t" FROM t1_mysql WHERE f1->>"$.t" <> 'NULL' order by autopk;
f1->>"$.t"
a
b
c
# Error cases (using MariaDB error codes/behaviors)
# MariaDB allows NULL on the RHS (returns NULL)
SELECT f1->>NULL FROM t1_mysql;
f1->>NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
# Invalid path returns a warning
SELECT f1 ->> "NULL" FROM t1_mysql;
f1 ->> "NULL"
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
Warnings:
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
Warning 4042 Syntax error in JSON path in argument 2 to function 'json_extract' at position 1
INSERT INTO t1_mysql(f1) VALUES
('[ { "a": 1 }, { "a": 2 } ]'),
('{ "a" : "foo", "b" : [ true, { "c" : 123, "c" : 456 } ] }'),
('{ "a" : "foo", "b" : [ true, { "c" : "123" } ] }'),
('{ "a" : "foo", "b" : [ true, { "c" : 123 } ] }');
SELECT
f1->>"$**.b",
JSON_UNQUOTE(JSON_EXTRACT(f1,"$**.b"))
FROM t1_mysql order by autopk;
f1->>"$**.b" JSON_UNQUOTE(JSON_EXTRACT(f1,"$**.b"))
NULL NULL
NULL NULL
NULL NULL
[3] [3]
[1] [1]
[2] [2]
NULL NULL
NULL NULL
NULL NULL
NULL NULL
[[true, {"c": 123, "c": 456}]] [[true, {"c": 123, "c": 456}]]
[[true, {"c": "123"}]] [[true, {"c": "123"}]]
[[true, {"c": 123}]] [[true, {"c": 123}]]
SELECT
f1->>"$.c",
JSON_UNQUOTE(JSON_EXTRACT(f1,"$.c"))
FROM t1_mysql order by autopk;
f1->>"$.c" JSON_UNQUOTE(JSON_EXTRACT(f1,"$.c"))
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
NULL NULL
DROP TABLE t1_mysql;
#
# 10. Ported tests from MySQL (Oracle). Authors at Oracle Corporation.
# Path: mysql-test/suite/json/t/json_prep_stmts.test
#
CREATE TABLE t1_prep(j JSON);
set @int=123;
set @intstr='123';
set @dec=3.14;
set @decstr='3.14';
set @flt=3.14E1;
set @fltstr='3.14E1';
set @strstr='xyz';
set @quotstr='"xyz"';
set @json='{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}';
insert into t1_prep values (@json);
prepare ps_get_int from "select * from t1_prep where j->'$.int' = ?";
prepare ps_get_dec from "select * from t1_prep where j->'$.dec' = ?";
prepare ps_get_flt from "select * from t1_prep where j->'$.flt' = ?";
prepare ps_get_str from "select * from t1_prep where j->'$.str' = ?";
execute ps_get_int using @int;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_int using @intstr;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_dec using @dec;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_dec using @decstr;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_flt using @flt;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_flt using @fltstr;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_str using @quotstr;
j
deallocate prepare ps_get_int;
deallocate prepare ps_get_dec;
deallocate prepare ps_get_flt;
deallocate prepare ps_get_str;
prepare ps_get_int from "select * from t1_prep where j->>'$.int' = ?";
prepare ps_get_dec from "select * from t1_prep where j->>'$.dec' = ?";
prepare ps_get_flt from "select * from t1_prep where j->>'$.flt' = ?";
prepare ps_get_str from "select * from t1_prep where j->>'$.str' = ?";
execute ps_get_int using @int;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_int using @intstr;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_dec using @dec;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_dec using @decstr;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_flt using @flt;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_flt using @fltstr;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
execute ps_get_str using @strstr;
j
{"int" : 123, "dec" : 3.14, "flt" : 3.14E1, "str" : "xyz", "array" : [1, 2, 4]}
deallocate prepare ps_get_int;
deallocate prepare ps_get_dec;
deallocate prepare ps_get_flt;
deallocate prepare ps_get_str;
DROP TABLE t1_prep;
End of 13.0 tests
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