I have a list ob objects. Each object contains several properties. Now I want to make a SELECT statement that gives me a list of a single property values. The simplified list look like this:
[
[
{
"day": "2021-10-01",
"entries": [
{
"name": "Start of competition",
"startTimeDelta": "08:30:00"
}
]
},
{
"day": "2021-10-02",
"entries": [
{
"name": "Start of competition",
"startTimeDelta": "03:30:00"
}
]
},
{
"day": "2021-10-03",
"entries": [
{
"name": "Start of competition"
}
]
}
]
]
The working SELECT is now
SELECT
JSON_EXTRACT(column, '$.days[*].entries[0].startTimeDelta') AS list
FROM table
The returned result is
[
"08:30:00",
"03:30:00"
]
But what I want to get (and also have expected) is
[
"08:30:00",
"03:30:00",
null
]
What can I do or how can I change the SELECT statement so that I also get NULL values in the list?
SELECT startTimeDelta
FROM test
CROSS JOIN JSON_TABLE(val,
'$[*][*].entries[*]' COLUMNS (startTimeDelta TIME PATH '$.startTimeDelta')) jsontable
https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=491f0f978d200a8a8522e3200509460e
Do you also have a working idea for MySQL< 8? – Lars
What is max amount of objects in the array on the 2nd level? – Akina
Well it's usually less than 10 – Lars
SELECT JSON_EXTRACT(val, CONCAT('$[0][', num, '].entries[0].startTimeDelta')) startTimeDelta
FROM test
-- up to 4 - increase if needed
CROSS JOIN (SELECT 0 num UNION SELECT 1 UNION SELECT 2 UNION SELECT 3) nums
WHERE JSON_EXTRACT(val, CONCAT('$[0][', num, '].entries[0]')) IS NOT NULL;
https://www.db-fiddle.com/f/xnCCSTGQXevcpfPH1GAbUo/0
Related
I have a JSON column "jobs" that looks like this:
[
{
"id": "1",
"done": "100",
"target": "100",
"startDate": "123123132",
"lastAction": "123123132",
"status": "0"
},
{
"id": "2",
"done": "10",
"target": "20",
"startDate": "2312321",
"lastAction": "2312321",
"status": "1"
}
]
I want to filter the array by object key values. For example: To find all items that have target > done, status != 0 and lastAction is yesterday to get response like this:
[
{
"id": "1",
"done": "19",
"target": "100",
"startDate": "123123132",
"lastAction": "123123132",
"status": "0"
}
]
I know I can extract the data to a JSON_TABLE() to do the filtering but I don't get the original object back(unless I recreate it back) and the solution is not dynamic.
Can this kind of array filtering can really be done in MySQL?
SELECT JSON_PRETTY(JSON_EXTRACT(jobs.jobs, CONCAT('$[', j.rownum-1, ']'))) AS object
FROM jobs
CROSS JOIN JSON_TABLE(
jobs.jobs, '$[*]' COLUMNS(
rownum for ordinality,
done int path '$.done',
target int path '$.target',
status int path '$.status'
)
) as j
WHERE j.target > j.done AND j.status != 0;
You also mentioned a condition on lastAction, but the example values you gave are not valid dates, so I'll leave that enhancement to you. The example above demonstrates the technique.
Yes it is possible to do it using the JSON_EXTRACT and JSON_SEARCH functions.
Let's say your table is named tbl_Jobs and the jobs column is of type JSON.
SELECT * FROM tbl_Jobs
WHERE JSON_EXTRACT(jobs, "$[*].target") = JSON_EXTRACT(jobs, "$[*].done")
AND JSON_EXTRACT(jobs, "$[*].status") != 0
AND JSON_SEARCH(jobs, 'one', DATE_SUB(CURDATE(), INTERVAL 1 DAY), NULL, "$[*].lastAction") IS NOT NULL
I have documents in a bucket called blocks in the following format:
{
"random_field": 1,
"transactions": [{
"id": "CCCCC",
"inputs": [{
"tx_id": "AAAAA",
"index": 0
},{
"tx_id": "BBBBB",
"index": 1
}]
}]
}
{
"transactions": [{
"id": "AAAAA",
"outputs": [{
"field1": "value123",
"field2": "value456"
},{
"field1": "ignore",
"field2": "ignore"
}]
}]
}
{
"transactions": [{
"id": "BBBBB",
"outputs": [{
"field1": "ignored",
"field2": "ignored"
},{
"field1": "value999",
"field2": "value888"
}]
}]
}
and I need to map the inputs from the first document to the corresponding outputs of the second and third documents. The way to do it manually is to, for each input, find a transaction with id equal to the input's tx_id, and then get the item from the outputs array based on the index of the input. To exemplify, this is the object I would like to return in this scenario:
{
"random_field": 1,
"transactions": [{
"id": "CCCCC",
"inputs": [{
"tx_id": "AAAAA",
"index": 0,
"output": {
"field1": "value123",
"field2": "value456"
}
},{
"tx_id": "BBBBB",
"index": 1,
"output": {
"field1": "value999",
"field2": "value888"
}
}]
}]
}
I managed to come up with the following query:
SELECT b.random_field,
b.transactions -- how to map this?
FROM blocks b
UNNEST b.transactions t
UNNEST t.inputs input
JOIN blocks `source` ON (ANY tx IN `source`.transactions SATISFIES tx.`id` = input.tx_id END)
UNNEST `source`.transactions source_tx
UNNEST source_tx.outputs o
WHERE (ANY tx IN b.transactions SATISFIES tx.`id` = 'AAAAA' END) LIMIT 1;
I suppose there should be a way to map b.transactions.inputs by using source_tx.outputs, but I couldn't find how.
I came across this other answer, but I don't really understand how it applies to my scenario. Maybe it does, but I am very new to Couchbase, so I am very much lost: How to map array values in one document to another and display in result
Basically you want inline some other document into current document using condition.
Instead of JOINs+ GROUPS use subquery expressions + correlated subqueries. (b.*, "abc" AS transactions, selects all fields of b and adds transactions (if already exist overwrite else adds)
CREATE INDEX ix1 ON blocks (ALL ARRAY FOR ot.id FOR ot IN transactions END);
SELECT b.*,
(SELECT t.*,
(SELECT i.*,
(SELECT RAW ot
FROM blocks AS o
UNNEST o.transactions AS ot
UNNEST ot.outputs AS oto
WHERE i.tx_id = ot.id AND i.`index` = UNNEST_POS(oto))[0] AS output
FROM t.`inputs` AS i) AS inputs
FROM b.transactions AS t) AS transactions
FROM blocks AS b
WHERE ANY tx IN b.transactions SATISFIES tx.`inputs` IS NOT NULL END ;
OR
SELECT b.*,
(SELECT t.*,
(SELECT i.*,
(SELECT RAW ot.outputs[i.`index`]
FROM blocks AS o
UNNEST o.transactions AS ot
WHERE i.tx_id = ot.id
LIMIT 1)[0] AS output
FROM t.`inputs` AS i) AS inputs
FROM b.transactions AS t) AS transactions
FROM blocks AS b
WHERE ANY tx IN b.transactions SATISFIES tx.`inputs` IS NOT NULL END ;
I have searched and can't seem to find somewhere doing exactly what I am trying.
I have a json similar to as follows in multiple rows in my database:
{
"date": "0001-01-01T00:00:00",
"details": {
"detail": [
{
"item": "11",
"value": "xt"
},
{
"item": "12",
"value": "xy"
},
{
"item": "13",
"value": "xz"
},
{
"item": "14",
"value": "zz"
}
]
}
}
I want to do sql that does this:
select ID
jsonColumn.value where item=11 as X
jsonColumn.value where item=12 as Y
from tbl
So I have results like this
----------------------
|ID |X |Y |
----------------------
|1 |xt |xy |
----------------------
I have tried using JSONVALUE but I seem to need to do it by the array item number like this:
'$.details.detail[3].value'
which doesn't really work
I have also tried this:
SELECT id, x.item, x.value
FROM
tbl F
CROSS APPLY (select *
FROM OPENJSON(F.Json,'$.details.detail')
CROSS APPLY OPENJSON(value)
WITH (item NVARCHAR(25) '$.item',
value NVARCHAR(max) '$.value') As x
where F.ID=55
Which I can use to print out all the items and values but then I'd have to query each separately again.
Is there a way of combining the two in to one big query that won't be completely inefficient?
Seems what you want is a pivot. I personally use conditional aggregation over the far more restrictive PIVOT operator. The JSON you supplied was invalid, so I took some liberties correcting it in my sandbox environment:
SELECT --ID,
MAX(CASE d.item WHEN 11 THEN d.[value] END) AS X,
MAX(CASE d.item WHEN 12 THEN d.[value] END) AS Y
FROM (VALUES(#JSON))V(J) --Your Table
CROSS APPLY OPENJSON(V.J,'$.details')
WITH (detail nvarchar(MAX) AS JSON ) OJ
CROSS APPLY OPENJSON(OJ.detail)
WITH(item int,
[value] nvarchar(2)) d;
If you are using this against a table, and not limiting the data to a single row, you'll need to also add a GROUP BY clause on the relevant columns (ID?).
I'm trying to compare 2 arrays in a sql query. Everything seems to work fine while getting data from dynamodb and MQTT broker server.
But if I try to compare both arrays, doesn't return anything or its undefined.
My sql query:
SELECT ts, objects, (SELECT id FROM get_dynamodb('table', 'key_name', 'key_value', 'rolearn').ids) AS db, (SELECT id from objects) as obj_ids
FROM 'subscribed/topic'
WHERE objects <> []
Result:
{
"ts": 1615807935588,
"objects": [
{
"id": 1,
"planet": "jupiter"
},
{
"id": 2,
"planet": "mars"
},
],
"db": [
{
"id": 2
},
{
"id": 3
}
],
"obj_ids": [
{
"id": 1
},
{
"id": 2
}
]
}
So far it's ok, now all I want to do is compare if "obj_ids" and "db" arrays are different (obj_ids <> db), and by the aws documentation https://docs.aws.amazon.com/iot/latest/developerguide/iot-sql-operators.html#iot-sql-operators-not-eq I can compare both arrays.
So if I do:
SELECT ts, objects, (SELECT id FROM get_dynamodb('table', 'key_name', 'key_value', 'rolearn').ids) AS db, (SELECT id from objects) as obj_ids
FROM 'subscribed/topic'
WHERE objects <> []
AND obj_ids <> db
The code doesn't return anything. I've already tested comparing 2 objects arrays hardcoded into the query and it works just has I intended.
SELECT ([{"id": 1},{"id": 2}] <> [{"id": 1}]) as result
FROM 'subscribed/topic'
Result:
{
"result": true
}
Any response will be appretiated.
Thanks!
Credits from Ben T
As AWS Docs WHERE clause says:
"you cannot reference any aliases created with the AS keyword in the SELECT. The WHERE clause is evaluated first, to determine if SELECT is evaluated."
So all I needed to do is move the (SELECT id FROM get_dynamodb('table', 'key_name', 'key_value', 'rolearn').ids) and (SELECT id from objects) to the WHERE clause.
Final query:
SELECT ts, objects
FROM 'subscribed/topic'
WHERE objects <> []
AND (SELECT id from objects) <> (SELECT id FROM get_dynamodb('table', 'key_name', 'key_value', 'rolearn').ids)
I have data like this:
[
{"name": "pratha", "email": "p#g.com", "sub": { "id": 1 } },
{"name": "john", "email": "x#x.com", "sub": { "id": 5 } },
{"name": "pratha", "email": "c#d.com", "sub": { "id": 2 } }
]
This is my query to get unique and latest emails:
SELECT DISTINCT ON (jae.e->>'name')
jae.e->>'name' as name,
jae.e->>'email' as email
FROM survey_results sr
CROSS JOIN LATERAL jsonb_array_elements(sr.data_field) jae (e)
ORDER BY jae.e->>'name', jae.e->'sub'->>'id' desc
Problem is, when I add count(*) to select, all counts are equal.
I want to get unique result with distinct, and count their occurrences. So in this case, pratha should be 2 and john should be 1
with their data (not just counts)
How can achieve this with PostgreSQL?
See here: https://dbfiddle.uk/?rdbms=postgres_11&fiddle=f5c640958c3e4d594287632d0f4a835f
Do you need this?
SELECT DISTINCT ON (jj->>'name') jj->>'name', jj->>'email' , count(*) over(partition by jj->>'name' )
from survey_results
join lateral jsonb_array_elements(data_field) j(jj) on true
ORDER BY jj->>'name', jj->'sub'->>'id' desc
https://dbfiddle.uk/?rdbms=postgres_11&fiddle=5f07b7bcb0001ebe32aa2f1338d9d0f0