MariaDB JSON remove key and its values - mariadb

Question

I have a TABLBE like
CREATE TABLE `saved_links` (
`link_entry_id` bigint(20) NOT NULL AUTO_INCREMENT,
`link_id` varchar(30) COLLATE utf8mb4_unicode_ci NOT NULL,
`user_data_json` longtext CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL,
PRIMARY KEY (`link_entry_id`),
UNIQUE KEY `link_id` (`link_id`)
) ENGINE=InnoDB AUTO_INCREMENT=19 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='saved Links'
AND INSERT
INSERT INTO `saved_links`(`link_id`, `user_data_json` )
VALUES (
'AABBCC',
'[{
"mama#gmail_DOT_com": {"u_email": "mama#gmail_DOT_com", "private": "no"}},
{
"papa#gmail_DOT_com": {"u_email": "papa#gmail_DOT_com", "private": "no"}},
{
"daughter#gmail_DOT_com": {"u_email": "daughter#gmail_DOT_com", "private": "no"}},
{
"son#gmail_DOT_com": {"u_email": "son#gmail_DOT_com", "private": "no"}
}]'
), (
'DDEEFF',
'[{
"mama#gmail_DOT_com": {"u_email": "mama#gmail_DOT_com", "private": "no"}},
{
"papa#gmail_DOT_com": {"u_email": "papa#gmail_DOT_com", "private": "no"}}
]'
) ;
SELECT*
---------------------------------------------------
`link_id` | `user_data_json`
----------------------------------------------------
`AABBCC` | [{
| "mama#gmail_DOT_com": {"u_email": "mama#gmail_DOT_com", "private": "no"}},
| {
| "papa#gmail_DOT_com": {"u_email": "papa#gmail_DOT_com", "private": "no"}},
| {
| "daughter#gmail_DOT_com": {"u_email": "daughter#gmail_DOT_com", "private": "no"}},
| {
| "son#gmail_DOT_com": {"u_email": "son#gmail_DOT_com", "private": "no"}}]
---------------------------------------------------------------------------------------------
`DDEEFF` | [{
| "mama#gmail_DOT_com": {"u_email": "mama#gmail_DOT_com", "private": "no"}},
| {
| "papa#gmail_DOT_com": {"u_email": "papa#gmail_DOT_com", "private": "no"}}
| ]
---------------------------------------------------------------------------------------------
I would like to REMOVE "papa#gmail_DOT_com" and all his values from AABBCC
I have tried (Am using 10.4.15-MariaDB)
UPDATE `saved_links`
SET `user_data_json` = IFNULL(
JSON_REMOVE( `user_data_json`, JSON_UNQUOTE(
REPLACE( JSON_SEARCH(
`user_data_json`, 'all', 'papa#gmail_DOT_com', NULL, '$**.papa#gmail_DOT_com'), '.u_email', '' ) ) ), `user_data_json` )
where `link_id` = 'AABBCC'
This returns
---------------------------------------------------
`link_id` | `user_data_json`
----------------------------------------------------
`AABBCC` | [{
| "mama#gmail_DOT_com": {"u_email": "mama#gmail_DOT_com", "private": "no"}},
| {}, //-> Notice these empty braces that are left behind.
| {
| "daughter#gmail_DOT_com": {"u_email": "daughter#gmail_DOT_com", "private": "no"}},
| {
| "son#gmail_DOT_com": {"u_email": "son#gmail_DOT_com", "private": "no"}}]
Is there a way to avoid having the empty {} after removal?
UPDATE01- If you try:
UPDATE `saved_links` SET
`user_data_json` =
JSON_REMOVE(`user_data_json`, '$.papa#gmail_DOT_com')
WHERE `link_id`= 'AABBCC'
This deletes all data in the column user_data_json WHERE link_id= 'AABBCC'`
Thank you

Answer 1

select json_remove(user_data_json,'$[1]') from saved_links where link_entry_id=19;
will return:
[{"mama#gmail_DOT_com": {"private": "no", "u_email": "mama#gmail_DOT_com"}},
{"daughter#gmail_DOT_com": {"private": "no", "u_email": "daughter#gmail_DOT_com"}},
{"son#gmail_DOT_com": {"private": "no", "u_email": "son#gmail_DOT_com"}}]
I am not really using JSON, but got my inspiration from the second example here: https://mariadb.com/kb/en/json_remove/
EDIT:
You could optimize this:
with recursive abc as (
Select 0 as i
union all
select i+1 from abc where i<2)
select link_entry_id, link_id,i, json_keys(user_data_json,concat('$[',i,']'))
from saved_links,abc;
output:
+---------------+---------+------+----------------------------------------------+
| link_entry_id | link_id | i | json_keys(user_data_json,concat('$[',i,']')) |
+---------------+---------+------+----------------------------------------------+
| 19 | AABBCC | 0 | ["mama#gmail_DOT_com"] |
| 20 | DDEEFF | 0 | ["mama#gmail_DOT_com"] |
| 19 | AABBCC | 1 | ["papa#gmail_DOT_com"] |
| 20 | DDEEFF | 1 | ["papa#gmail_DOT_com"] |
| 19 | AABBCC | 2 | ["daughter#gmail_DOT_com"] |
| 20 | DDEEFF | 2 | NULL |
+---------------+---------+------+----------------------------------------------+
With this you could 'convert' "papa#gm...." to 1.
EDIT2:
Combining different JSON functions from Mariadb or from MySQL can do a lot:
SELECT
j.person,
JSON_KEYS(j.person),
JSON_EXTRACT(JSON_KEYS(j.person),'$[0]'),
JSON_UNQUOTE(JSON_EXTRACT(JSON_KEYS(j.person),'$[0]')),
JSON_VALUE(JSON_KEYS(j.person),'$[0]')
FROM
JSON_TABLE('[{
"mama#gmail_DOT_com": {"u_email": "mama#gmail_DOT_com", "private": "no"}},
{
"papa#gmail_DOT_com": {"u_email": "papa#gmail_DOT_com", "private": "no"}},
{
"daughter#gmail_DOT_com": {"u_email": "daughter#gmail_DOT_com", "private": "no"}},
{
"son#gmail_DOT_com": {"u_email": "son#gmail_DOT_com", "private": "no"}
}]',
'$[*]' COLUMNS(person JSON PATH '$[0]')) j
output (please scroll right, the last column is more interesting than the first column 😉):
+ ----------- + ------------------------ + --------------------------------------------- + ----------------------------------------------------------- + ------------------------------------------- +
| person | JSON_KEYS(j.person) | JSON_EXTRACT(JSON_KEYS(j.person),'$[0]') | JSON_UNQUOTE(JSON_EXTRACT(JSON_KEYS(j.person),'$[0]')) | JSON_VALUE(JSON_KEYS(j.person),'$[0]') |
+ ----------- + ------------------------ + --------------------------------------------- + ----------------------------------------------------------- + ------------------------------------------- +
| {"mama#gmail_DOT_com": {"private": "no", "u_email": "mama#gmail_DOT_com"}} | ["mama#gmail_DOT_com"] | "mama#gmail_DOT_com" | mama#gmail_DOT_com | mama#gmail_DOT_com |
| {"papa#gmail_DOT_com": {"private": "no", "u_email": "papa#gmail_DOT_com"}} | ["papa#gmail_DOT_com"] | "papa#gmail_DOT_com" | papa#gmail_DOT_com | papa#gmail_DOT_com |
| {"daughter#gmail_DOT_com": {"private": "no", "u_email": "daughter#gmail_DOT_com"}} | ["daughter#gmail_DOT_com"] | "daughter#gmail_DOT_com" | daughter#gmail_DOT_com | daughter#gmail_DOT_com |
| {"son#gmail_DOT_com": {"private": "no", "u_email": "son#gmail_DOT_com"}} | ["son#gmail_DOT_com"] | "son#gmail_DOT_com" | son#gmail_DOT_com | son#gmail_DOT_com |
+ ----------- + ------------------------ + --------------------------------------------- + ----------------------------------------------------------- + ------------------------------------------- +
EDIT (2020-12-26):
I did have a look at mariadb, and below is tested on version 10.5.8.
select json_extract(json_array(user_data_json,"papa#gmail_DOT_com"), '$[1]') from saved_links;
+-----------------------------------------------------------------------+
| json_extract(json_array(user_data_json,"papa#gmail_DOT_com"), '$[1]') |
+-----------------------------------------------------------------------+
| "papa#gmail_DOT_com" |
| "papa#gmail_DOT_com" |
+-----------------------------------------------------------------------+
But use of $[1] is not desired, soe whe have to determine the correct value for 1:
WITH RECURSIVE data AS (
SELECT
link_entry_id,
link_id,
0 as I,
JSON_KEYS(user_data_json, '$[0]') jk
FROM saved_links
UNION ALL
SELECT
sl.link_entry_id,
sl.link_id,
I+1,
JSON_KEYS(user_data_json, CONCAT('$[',i+1,']'))
FROM saved_links sl, (select max(i) as I from data) x
WHERE JSON_KEYS(user_data_json, CONCAT('$[',i+1,']'))<>'')
SELECT * FROM data
;
.
+---------------+---------+------+----------------------------+
| link_entry_id | link_id | I | jk |
+---------------+---------+------+----------------------------+
| 19 | AABBCC | 0 | ["mama#gmail_DOT_com"] |
| 20 | DDEEFF | 0 | ["mama#gmail_DOT_com"] |
| 19 | AABBCC | 1 | ["papa#gmail_DOT_com"] |
| 20 | DDEEFF | 1 | ["papa#gmail_DOT_com"] |
| 19 | AABBCC | 2 | ["daughter#gmail_DOT_com"] |
| 19 | AABBCC | 3 | ["son#gmail_DOT_com"] |
+---------------+---------+------+----------------------------+
I is the correct value for finding papa#gmail_DOT_com
WITH RECURSIVE data AS (
SELECT
link_entry_id,
link_id,
0 as I,
JSON_KEYS(user_data_json, '$[0]') jk
FROM saved_links
UNION ALL
SELECT
sl.link_entry_id,
sl.link_id,
I+1,
JSON_KEYS(user_data_json, CONCAT('$[',i+1,']'))
FROM saved_links sl, (select max(i) as I from data) x
WHERE JSON_KEYS(user_data_json, CONCAT('$[',i+1,']'))<>'')
SELECT
json_remove(user_data_json, concat('$[',I,']'))
FROM saved_links sl
INNER JOIN data d ON d.link_entry_id= sl.link_entry_id AND d.link_id=sl.link_id and d.I=1
;
.
[{"mama#gmail_DOT_com": {"u_email": "mama#gmail_DOT_com", "private": "no"}},
{"daughter#gmail_DOT_com": {"u_email": "daughter#gmail_DOT_com", "private": "no"}},
{"son#gmail_DOT_com": {"u_email": "son#gmail_DOT_com", "private": "no"}}]
[{"mama#gmail_DOT_com": {"u_email": "mama#gmail_DOT_com", "private": "no"}}]

Answer 2

I've played some time with this puzzle and I figured in another way to do it.
You can use json_search (plus to other functions) to finally use json_remove.
Once you a creating an array of jsons, we must consider it are your designer decision to upload data as is.
So, this is my code:
UPDATE saved_links sl
SET user_data_json =
JSON_REMOVE(user_data_json,
SUBSTRING_INDEX(
JSON_UNQUOTE(
JSON_SEARCH(sl.user_data_json,'one','papa#gmail_DOT_com')
)
,'.', 1)
)
WHERE link_id='AABBCC'
json_search(sl.user_data_json,'one','papa#gmail_DOT_com')
Returns "$[1].papa#gmail_DOT_com.u_email"
JSON_UNQUOTE
Returns $[1].papa#gmail_DOT_com.u_email
SUBSTRING_INDEX(#JSON,'.',1)
Returns $[1]
And finally you will use this last return as JSON_REMOVE path.
I don't know if your JSON key will be always the same of u_email but if it's true, then you can use it.