I'm trying to "translate" a query from MySQL,
SELECT a.Nome, a.PosicaoPrimaria, a.PosicaoSecundaria
FROM Atleta AS a INNER JOIN Equipa AS e ON a.Equipa_idEquipa = e.idEquipa
WHERE e.Localidade = 'Braga' AND a.PosicaoSecundaria != ''
ORDER BY a.PosicaoSecundaria;
to a MongoDB query. So far, so good. I've searched to try and understand how I can manage to do what I want, but I have come to a halt.
So far, this is what I have as a MongoDB query,
db.Atleta.aggregate([
{$lookup:
{from:"Equipa",
let: {e:"$Equipa_idEquipa", ps:"$PosicaoSecundaria"},
pipeline:[
{$match:
{$expr:
{$and: [ {$eq:["$idEquipa", "$$e"]},
{$ne:[null, "$$ps"]},
{$eq:["$Localidade", "Braga"]} ] } } }],
as:"Query" }},
{$project:{Query:1, Nome:1, PosicaoPrimaria:1, PosicaoSecundaria:1, _id:0}} ]).pretty()
This gives me the results I want in the players I want to be returned, but it also returns all the other players, who 'don't fit the bill' on the query. See image below.
Query results
What I really need, is to filter the results to only show the players who have the "Query" array as not empty. Is there a way that can be done?
Related
I'm starting to explore the JSON1 library for sqlite and have been so far successful in the basic queries I've created. I'm now looking to create a more complicated query that pulls data from multiple levels.
Here's the example JSON object I'm starting with (and most of the data is very similar).
{
"height": 140.0,
"id": "cp",
"label": {
"bind": "cp_label"
},
"type": "color_picker",
"user_data": {
"my_property": 2
},
"uuid": "948cb959-74df-4af8-9e9c-c3cb53ac9915",
"value": {
"bind": "cp_color"
},
"width": 200.0
}
This json object is buried about seven levels deep in a json structure and I pulled it from the larger json construct using an sql statement like this:
SELECT value FROM forms, json_tree(forms.formJSON, '$.root')
WHERE type = 'object'
AND json_extract(value, '$.id') = #sControlID
// In this example, #sControlID is a variable that represents the `id` value we're looking for, which is 'cp'
But what I really need to pull from this object are the following:
the value from key type ("color_picker" in this example)
the values from keys bind ("cp_color" and "cp_label" in this example)
the keys value and label (which have values of {"bind":"<string>"} in this example)
For that last item, the key name (value and label in this case) can be any number of keywords, but no matter the keyword, the value will be an object of the form {"bind":"<some_string>"}. Also, there could be multiple keys that have a bind object associated with them, and I'd need to return all of them.
For the first two items, the keywords will always be type and bind.
With the json example above, I'd ideally like to retrieve two rows:
type key value
color_picker value cp_color
color_picker label cp_label
When I use json_extract methods, I end up retrieving the object {"bind":"cp_color"} from the json_tree table, but I also need to retrieve the data from the parent object. I feel like I need to do some kind of union, but my attempts have so far been unsuccessful. Any ideas here?
Note: if the {"bind":"<string>"} object doesn't exist as a child of the parent object, I don't want any rows returned.
Well, I was on the right track and eventually figured out it. I created a separate query for each of the items I was looking for, then INNER JOINed all the json_tree tables from each of the queries to have all the required fields available. Then I json_extracted the required data from each of the json fields I needed data from. In the end, it gave me exactly what I was looking for, though I'm sure it could be written more efficiently.
For anyone interested, this is what hte final query ended up looking like:
SELECT IFNULL(json_extract(parent.value, '$.type'), '_window_'), child.key, json_extract(child.value, '$.bind') FROM (SELECT json_tree.* FROM nui_forms, json_tree(nui_forms.formJSON, '$') WHERE type = 'object' AND json_extract(nui_forms.formJSON, '$.id') = #sWindowID) parent INNER JOIN (SELECT json_tree.* FROM nui_forms, json_tree(nui_forms.formJSON, '$') WHERE type = 'object' AND json_extract(value, '$.bind') != 'NULL' AND json_extract(nui_forms.formJSON, '$.id') = #sWindowID) child ON child.parent = parent.id;
If you have any tips on reducing its complexity, feel free to comment!
Is there a way to get the output of a MySQL query to list rows in the following structure
{
1:{voo:bar,doo:dar},
2:{voo:mar,doo:har}
}
as opposed to
[
{id:1,voo:bar,doo:dar},
{id:2,voo:mar,doo:har}
]
which I then have to loop through to create the desired object?
I should add that within each row I am also concatenating results to form an object, and from what I've experimented with you can't group_concatenate inside a group_concatenation. As follows:
knex('table').select(
'table.id',
'table.name',
knex.raw(
`CONCAT("{", GROUP_CONCAT(DISTINCT
'"',table.voo,'"',':','"',table.doo,'"'),
"}") AS object`
)
.groupBy('table.id')
Could GROUP BY be leveraged in any way to achieve this? Generally I'm inexperienced at SQL and don't know what's possible and what's not.
Suppose we have table person and table phoneand the relation between them is one to many.
I need to retrieve this like result with one query.
[
{
name:"abc",
lname:"def",
phones:[
{
dial_code="+1",
number:"12345667"
},
{
dial_code="+1",
number:"12345667"
}
]
},
{
name:"xyz",
lname:"lmn",
phones[
{
dial_code="+2",
number:"2643525"
}
]
},
{...}
]
I can do this by multiple query like first getting all persons and then get their phones one by one but i think its so weird and need lots of time and reduce performance. and if i get all data by joining table it wouldn't be like this JSON format.
Any idea will be appreciated.
Sorry for my bad English.
First things first, you cannot retrieve the desired result with multiple phone inside each person with one single query.
Now, running the query inside person loop will hugely affect the performance of the script if there are a lot of data. In this way, first, you need to execute a query to fetch all persons(say n persons). Then you have to again loop all n persons to fetch their respective phones.
So you need to run something like following inside $persons loop n times:
SELECT * FROM phone WHERE person_id = [$person_id]
Therefore in this way you need to execute n+1 queries.
To overcome this n+1 query problem we can apply a methodology which is called as eager loading. Here you also need to execute the first query to retrieve all persons and then write a query to fetch all phones which belongs to those retrieved persons:
SELECT * FROM person
Result($persons):
id name
5 John
10 Bob
20 Jenna
SELECT * FROM phone WHERE person_id IN (5,10,20)
Result($phones):
id person_id dial_code number
1 5 +2 12345
2 10 +1 12312
3 20 +1 98765
Now we combine these two results in PHP scripts to produce the desired array. In this way, we write only two queries instead of n+1 queries.
You can write a PHP script like following to combine the two result sets:
// Create an array of phones with person_id as key
$phones_with_person_id_as_key = [];
foreach($phones as $key => $phone) {
$phones_with_person_id_as_key[$phone->person_id][$key] = $phone;
}
// Loop $persons array and add phones to person object
foreach($persons as $key => $person) {
// create phones key and add data
if (!empty($phones_with_person_id_as_key[$person->id])) {
$person->phones = $phones_with_person_id_as_key[$person->id];
}
else {
$person->phones = [];
}
}
Now $persons contains the formatted desired output.
I am new to couchbase and I have been going through couchbase documents and other online resources for a while but I could't get my query working. Below is the data structure and my query:
Table1:
{
"jobId" : "101",
"jobName" : "abcd",
"jobGroup" : "groupa",
"created" : " "2018-05-06T19:13:43.318Z",
"region" : "dev"
},
{
"jobId" : "102",
"jobName" : "abcd2",
"jobGroup" : "groupa",
"created" : " "2018-05-06T22:13:43.318Z",
"region" : "dev"
},
{
"jobId" : "103",
"jobName" : "abcd3",
"jobGroup" : "groupb",
"created" : " "2018-05-05T19:11:43.318Z",
"region" : "test"
}
I need to get the jobId which has the latest job information (max on created timestamp) for a given jobGroup and region (group by jobGroup and region).
My sql query doesn't help me using self-join on jobId.
Query:
/*
Idea is to pull out the job which was executed latest for all possible groups and region and print the details of that particular job
select * from (select max(DATE_FORMAT_STR(j.created,'1111-11-11T00:00:00+00:00')) as latest, j.jobGroup, j.region from table1 j
group by jobGroup, region) as viewtable
join table t
on keys meta(t).id
where viewtable.latest in t.created and t.jobGroup = viewtable.jobGroup and
viewtable.region = t.region
Error Result: No result displayed
Desired result :
{
"jobId" : "102",
"jobName":"abcd2",
"jobGroup":"groupa",
"latest" :"2018-05-06T22:13:43.318Z",
"region":"dev"
},
{
"jobId" : "103",
"jobName" : "abcd3",
"jobGroup" : "groupb",
"created" : " "2018-05-05T19:11:43.318Z",
"region" : "test"
}
If I understand your query correctly, this can be answered using 'group by' and no join. I tried entering your sample data and the following query gives the correct result:
select max([created,d])[1] max_for_group_region
from default d
group by jobGroup, region;
How does it work? It uses 'group by' to group documents by jobGroup and region, then creates a two-element array holding, for every document in the group:
the 'created' timestamp field
the document where the timestamp came from
It then applies the max function on the set of 2-element arrays. The max of a set of arrays looks for the maximum value in the first array position, and if there's a tie look at the second position, and so on. In this case we are getting the two-element array with the max timestamp.
Now we have an array [ timestamp, document ], so we apply [1] to extract just the document.
I'm seeing some inconsistencies and invalid JSON in your examples, so I'm going to do the best I can. First off, I'm using Couchbase Server 5.5 which provides the new ANSI JOIN syntax. There might be a way to do this in an earlier version of Couchbase Server.
Next, I created an index on the created field: CREATE INDEX ix_created ON bucketname(created).
Then, I use a subquery to get the latest date, aggregated by jobGroup and region. I then join the latest date from this query to the entire bucket and select the fields that (I think) you want in your desired result:
SELECT k.jobId, k.jobName, k.jobGroup, k.created AS latest, k.region
FROM (
SELECT j.jobGroup, j.region, MAX(j.created) as latestDate
FROM so j
GROUP BY j.jobGroup, j.region
) dt
LEFT JOIN so k ON k.created = dt.latestDate;
Problems with this approach:
If two documents have the exact same date, this isn't a reliable way to determine the latest. You can add a LIMIT 1 to the subquery, which would just pick one arbitrarily, or you could ORDER BY whatever your preference is.
Subquery performance: I don't know how large your data set is, but this could be pretty slow.
Requires Couchbase Server 5.5, which is currently in beta.
If you are using a different version of Couchbase Server, you may want to consider asking in the Couchbase N1QL Forums for a more expert answer.
I'm fairly new to couchbase and have tried to find the answer to a particular query I'm trying to create with not much success so far.
I've debated between using a view or N1QL for this particular case and settled with N1QL but haven't managed to get it to work so maybe a view is better after all.
Basically I have the document key (Group_1) for the following document:
Group_1
{
"cbType": "group",
"ID": 1,
"Name": "Group Atlas 3",
"StoreList": [
2,
4,
6
]
}
I also have 'store' documents, their keys are listed in this document's storelist. (Store_2, Store_4, Store_6 and they have a storeID value that is 2, 4 and 6) I basically want to obtain all 3 documents listed.
What I do have that works is I obtain this document with its id by doing:
var result = CouchbaseManager.Bucket.Get<dynamic>(couchbaseKey);
mygroup = JsonConvert.DeserializeObject<Group> (result.ToString());
I can then loop through it's storelist and obtain all it's stores in the same manner, but i don't need anything else from the group, all i want are the stores and would have prefered to do this in a single operation.
Does anyone know how to do a N1QL directly unto a specified document value?
Something like (and this is total imaginary non working code I'm just trying to clearly illustrate what I'm trying to get at):
SELECT * FROM mycouchbase WHERE documentkey IN
Group_1.StoreList
Thanks
UPDATE:
So Nic's solution does not work;
This is the closest I get to what I need atm:
SELECT b from DataBoard c USE KEYS ["Group_X"] UNNEST c.StoreList b;
"results":[{"b":2},{"b":4},{"b":6}]
Which returns the list of IDs of the Stores I want for any given group (Group_X) - I haven't found a way to get the full Stores instead of just the ID in the same statement yet.
Once I have, I'll post the full solution as well as all the speed bumps I've encountered in the process.
I apologize if I have a misunderstanding of your question, but I'm going to give it my best shot. If I misunderstood, please let me know and we'll work from there.
Let's use the following scenario:
group_1
{
"cbType": "group",
"ID": 1,
"Name": "Group Atlas 3",
"StoreList": [
2,
4,
6
]
}
store_2
{
"cbType": "store",
"ID": 2,
"name": "some store name"
}
store_4
{
"cbType": "store",
"ID": 4,
"name": "another store name"
}
store_6
{
"cbType": "store",
"ID": 6,
"name": "last store name"
}
Now lets say you wan't to query the stores from a particular group (group_1), but include no other information about the group. You essentially want to use N1QL's UNNEST and JOIN operators.
This might leave you with a query like so:
SELECT
stores.name
FROM `bucket-name-here` AS groups
UNNEST groups.StoreList AS groupstore
JOIN `bucket-name-here` AS stores ON KEYS ("store_" || groupstore.ID)
WHERE
META(groups).id = 'group_1';
A few assumptions are made in this. Both your documents exist in the same bucket and you only want to select from group_1. Of course you could use a LIKE and switch the group id to a percent wildcard.
Let me know if something doesn't make sense.
Best,
Try this query:
select Name
from buketname a join bucketname b ON KEYS a.StoreList
where Name="Group Atlas 3"
Based on your update, you can do the following:
SELECT b, s
FROM DataBoard c USE KEYS ["Group_X"]
UNNEST c.StoreList b
JOIN store_bucket s ON KEYS "Store_" || TO_STRING(b);
I have a similar requirement and I got what I needed with a query like this:
SELECT store
FROM `bucket-name-here` group
JOIN `bucket-name-here` store ON KEYS group.StoreList
WHERE group.cbType = 'group'
AND group.ID = 1