I'm trying to do select * from demo where demojson->'sub'->'item' = array("") but this doesn't work. I'd like to find the following
All rows where .sub.item in the JSON column is an array containing exactly one empty string ([""])
All rows where .sub.item in the JSON column is an array that may contain more than one item, but at least one of the items is an empty string. (["not empty", "also not empty", ""])
demojson column could contain for example
{
"key": "value",
"sub": {
"item": [""]
}
}
Have you tried
SELECT * from demo
WHERE demojson->'sub'->>'item' = '[""]';
Here ->> operator allows to get JSON object field as text.
And another solution
SELECT * from demo
WHERE json_array_length(demojson->'sub'->'item') = 1 AND
demojson->'sub'->'item'->>0 = '';
Here ->> operators allows to get JSON first array element as text.
Due JSONLint doesn't validate the supplied text example, I've used the next:
CREATE TABLE info (id int, j JSON);
insert into info values
(1, '{"key":"k1", "sub": {"item":["i1","i2"]}}'),
(2, '{"key":"k2", "sub": {"item":[""]}}'),
(3, '{"key":"k3", "sub": {"item":["i2","i3"]}}');
Using the where clause in this way, it works:
select * from info
where j->'sub'->>'item' = '[""]';
+----+------------------------------------+
| id | j |
+----+------------------------------------+
| 2 | {"key":"k2", "sub": {"item":[""]}} |
+----+------------------------------------+
Can check it here: http://rextester.com/VEPY57423
Try the following:
SELECT * FROM demo
WHERE demojson->'sub'->'item' = to_jsonb(ARRAY['']);
Related
I have a table which has a JSON column called people like this:
Id
people
1
[{ "id": 6 }, { "id": 5 }, { "id": 3 }]
2
[{ "id": 2 }, { "id": 3 }, { "id": 1 }]
...and I need to update the people column and put a 0 in the path $[*].id where id = 3, so after executing the query, the table should end like this:
Id
people
1
[{ "id": 6 }, { "id": 5 }, { "id": 0 }]
2
[{ "id": 2 }, { "id": 0 }, { "id": 1 }]
There may be more than one match per row.
Honestly, I didn´t tried any query since I cannot figure out how can I loop inside a field, but my idea was something like this:
UPDATE mytable
SET people = JSON_SET(people, '$[*].id', 0)
WHERE /* ...something should go here */
This is my version
SELECT VERSION()
+-----------------+
| version() |
+-----------------+
| 10.4.22-MariaDB |
+-----------------+
If the id values in people are unique, you can use a combination of JSON_SEARCH and JSON_REPLACE to change the values:
UPDATE mytable
SET people = JSON_REPLACE(people, JSON_UNQUOTE(JSON_SEARCH(people, 'one', 3)), 0)
WHERE JSON_SEARCH(people, 'one', 3) IS NOT NULL
Note that the WHERE clause is necessary to prevent the query replacing values with NULL when the value is not found due to JSON_SEARCH returning NULL (which then causes JSON_REPLACE to return NULL as well).
If the id values are not unique, you will have to rely on string replacement, preferably using REGEXP_REPLACE to deal with possible differences in spacing in the values (and also avoiding replacing 3 in (for example) 23 or 34:
UPDATE mytable
SET people = REGEXP_REPLACE(people, '("id"\\s*:\\s*)2\\b', '\\14')
Demo on dbfiddle
As stated in the official documentation, MySQL stores JSON-format strings in a string column, for this reason you can either use the JSON_SET function or any string function.
For your specific task, applying the REPLACE string function may suit your case:
UPDATE
mytable
SET
people = REPLACE(people, CONCAT('"id": ', 3, ' '), CONCAT('"id": ',0, ' '))
WHERE
....;
I have a table with a json field with the following json:
[
{
productId: '1',
other : [
otherId: '2'
]
},
{
productId: '3',
other : [
otherId: '4'
]
}
]
I am trying to select the productId and otherId for every array element like this:
select JSON_EXTRACT(items, $.items[].productId) from order;
But this is completely wrong since it takes only the first element in the array
Do I need to write a loop or something?
First of all, the data you show is not valid JSON. It has multiple mistakes that make it invalid.
Here's a demo using valid JSON:
mysql> create table orders ( items json );
mysql> insert into orders set items = '[ { "productId": "1", "other": { "otherId": "2" } }, { "productId": "3", "other" : { "otherId": "4" } } ]'
mysql> SELECT JSON_EXTRACT(items, '$[*].productId') AS productIds FROM orders;
+------------+
| productIds |
+------------+
| ["1", "3"] |
+------------+
If you want each productId on a row by itself as a scalar value instead of a JSON array, you'd have to use JSON_TABLE() in MySQL 8.0:
mysql> SELECT j.* FROM orders CROSS JOIN JSON_TABLE(items, '$[*]' COLUMNS(productId INT PATH '$.productId')) AS j;
+-----------+
| productId |
+-----------+
| 1 |
| 3 |
+-----------+
This is tested in MySQL 8.0.23.
You also tagged your question MariaDB. I don't use MariaDB, and MariaDB has its own incompatible implementation of JSON support, so I can't predict how it will work.
Thanks for helping.
I have my table CONVERSATIONS structured in columns like this :
[ ID , JSON_CONTENT ]
In the column ID i have a simple id in Varchar
In the column JSON_CONTENT i something like this :
{
"id_conversation" : "25bc8cbffa8b4223a2ed527e30d927bf",
"exchanges": [
{
"A" : "...",
"B": "..."
},
{
"A" : "...",
"B": "..."
},
{
"A" : "...",
"Z" : "..."
}
]
}
I would like to query and get the id and the last element of exchanges :
[ ID , LAST_ELT_IN_EXCHANGE_IN_JSON_CONTENT]
I wanted to do this :
select TOP 3 ID, JSON_QUERY(JSON_CONTENT, '$.exchange[-1]')
from CONVERSATION
But of course Transact SQL is not Python.
I saw theses answers, but i don't know how to applicate to my problem.
Select last value from Json array
Thanks for helping <3
If I understand you correctly, you need an additional APPLY operator and a combination of OPENJSON() and ROW_NUMBER(). The result from the OPENJSON() call is a table with columns key, value and type and when the JSON content is an array, the key column returns the index of the element in the specified array:
Table:
SELECT ID, JSON_CONTENT
INTO CONVERSATION
FROM (VALUES
(1, '{"id_conversation":"25bc8cbffa8b4223a2ed527e30d927bf","exchanges":[{"A":"...","B":"..."},{"A":"...","B":"..."},{"A":"...","Z":"..."}]}')
) v (ID, JSON_CONTENT)
Statement:
SELECT c.ID, j.[value]
FROM CONVERSATION c
OUTER APPLY (
SELECT [value], ROW_NUMBER() OVER (ORDER BY CONVERT(int, [key]) DESC) AS rn
FROM OPENJSON(c.JSON_CONTENT, '$.exchanges')
) j
WHERE j.rn = 1
Result:
ID value
------------------------
1 {
"A" : "...",
"Z" : "..."
}
Notice, that -1 is not a valid array index in your path expression, but you can access the item in a JSON array by index (e.g. '$.exchanges[2]').
I have a table with a column of the data type JSONB. Each row in the column has a JSON that looks something like this:
[
{
"A":{
"AA": "something",
"AB": false
}
},
{
"B": {
"BA":[
{
"BAAA": [1,2,3,4]
},
{
"BABA": {
....
}
}
]
}
}
]
Note: the JSON is a complete mess of lists and objects, and it has a total of 300 lines. Not my data but I am stuck with it. :(
I am using postgresql version 12
How would I write the following queries:
Return all row that has the value of AB set to false.
Return the values of BAAA is each row.
You can find the AB = false rows with a JSON Path query:
select *
from test
where data ## '$[*].A.AB == false'
If you don't know where exactly the key AB is located, you can use:
select *
from test
where data ## '$[*].**.AB == false'
To display all elements from the array as rows, you can use:
select id, e.*
from test
cross join jsonb_array_elements(jsonb_path_query_first(data, '$[*].B.BA.BAAA')) with ordinality as e(item, idx)
I include a column "id" as a placeholder for the primary key column, so that the source of the array element can be determined in the output.
Online example
I don't know why, but probably PHP persisted some of my data as object and some of them as array. My table looks something like:
seller_info_address Table:
ID (INT) | address (JSONB) |
------------+--------------------------------------------------|
1 | {"addressLines":{"0":"Technology Park",...},...} |
2 | {"addressLines":["Technology Park",...],...} |
Some addressLines are objects:
{
"addressLines": {
"0": "Technology Park",
"1": "Blanchard Road",
"3": "Dublin",
"4": "2"
},
"companyName": "...",
"emailAddress": [],
"...": "..."
}
Some addressLines are arrays:
{
"addressLines": [
"Technology Park",
"Blanchard Road",
"Dublin",
"2"
],
"companyName": "...",
"emailAddress": [],
"...": "..."
}
I would like to equalize the data with a SQL query, but I'm not sure how to do it. All addressLines persisted as object should be updated to array form.
I am grateful for help, thanks!
You can convert the objects to an array using this:
select id, (select jsonb_agg(e.val order by e.key::int)
from jsonb_each(sia.address -> 'addressLines') as e(key,val))
from seller_info_address sia
where jsonb_typeof(address -> 'addressLines') = 'object'
The where condition makes sure we only do this for addresslines that are not an array.
The aggregation used can also be used inside an UPDATE statement:
update seller_info_address
set address = jsonb_set(address, '{addressLines}',
(select jsonb_agg(e.val order by e.key::int)
from jsonb_each(address -> 'addressLines') as e(key,val))
)
where jsonb_typeof(address -> 'addressLines') = 'object';
Ok, I have now found a solution myself. Definitely not the most eloquent solution. I'm sure there's a nicer and more efficient one, but it works...
DROP FUNCTION update_address_object_to_array(id INTEGER);
CREATE OR REPLACE FUNCTION
update_address_object_to_array(id INTEGER)
RETURNS VOID AS
$UPDATE_ADDRESS_OBJECT_TO_ARRAY$
BEGIN
UPDATE seller_info_address
SET address = jsonb_set(address, '{addressLines}', (
SELECT CASE
WHEN jsonb_agg(addressLines) IS NOT NULL THEN jsonb_agg(addressLines)
ELSE '[]'
END
FROM seller_info_address sia,
jsonb_each(address #> '{addressLines}') as t(key, addressLines)
WHERE jsonb_typeof(sia.address -> 'addressLines') = 'object'
AND seller_info_id = update_address_object_to_array.id
), true)
WHERE seller_info_id = update_address_object_to_array.id
AND jsonb_typeof(address -> 'addressLines') = 'object';
END
$UPDATE_ADDRESS_OBJECT_TO_ARRAY$
LANGUAGE 'plpgsql';
SELECT update_address_object_to_array(sia.seller_info_id)
FROM seller_info_address sia
WHERE jsonb_typeof(address -> 'addressLines') = 'object';
The inner SELECT fetches all lines in the addressLines object using jsonb_each and then aggregates them into an array using jsonb_agg. The conditional expressions is to prevented null cases.
The result is then stored in the UPDATE via jsonb_set to the required position in the json. The WHERES should be self-explanatory.