I have to execute following query:
create dm_myobject object
set my_id_attribute = (select r_object_id from dm_otherobject where <some clause here>)
where ...
But subquery in brackets returns more than one id. I can't make whereclause more detailed to retrieve only one value.
How to take first?
ENABLE(FETCH_ALL_RESULTS 1) or ENABLE(RETURN_TOP 1) doesn't help.
In my experience it is impossible to use DQL hints in a sub query like you suggested, because the hint is applied to the query as a whole. It is indeed possible to use, say, ENABLE(RETURN_TOP 1) on a query that contains a sub query, however that hint will then be used on the outer query and never on the inner one. In your case, however, you'll end up with an error message telling that the sub query returns more than one result.
Try using an aggregate function on the selected attribute instead:
CREATE dm_myobject OBJECT
SET my_id_attribute = (
SELECT MIN(r_object_id)
FROM dm_otherobject
WHERE <some clause>
)
The MIN and MAX functions work with ints and strings, and I suspect they work with IDs too. Since it is ok for you to set only the first ID that's returned from your sub query, I suspect you're returning them in a sorted order and want to use the first -- hence the usage of the MIN function.
An alternative approach would of course be to write a script or a small Java program that executes several DQL statements, but that might or might not work for you in your case.
Related
I want to use result set of meta-function get_node_dependencies as a subquery. Is there some way to do it?
Something like this:
select v_txtindex.StringTokenizerDelim (dep, chr(10)) over () as words
from (
select get_node_dependencies() as dep
) t;
This query thows an error Meta-function ("get_node_dependencies") can be used only in the Select clause.
I know that there is a view vs_node_dependencies that returns the same data in more readable way, but the question is generic, not related to any specific meta-function.
Most Vertica meta functions returning a report are for informational purposes on the fly, and can only be used on the outmost part of a query - so you can't apply another function on their output.
But - as you are already prepared to go through development work to split that output into tokens, you might often be even better off by querying vs_node_dependencies directly. You'll also be more flexible - is my take on this.
I'm trying to filter an influx DB query (using the nodeJS influxdb-client library).
As far as I can tell, it only works with "flux" queries.
I would like to filter out all records that share a specific attribute with any record that matches a particular condition. I'm filtering using the filter-function, but I'm not sure how I can continue from there. Is this possible in a single query?
My filter looks something like this:
|> filter(fn:(r) => r["_value"] == 1 and r["button"] == "1" ) and I would like to leave out all the record that have the same r["session"] as any that match this filter.
Do I need two queries; one to get those r["session"]s and one to filter on those, or is it possible in one?
Update:
Trying the two-step process. Got the list of r["session"]s into an array, and attempting to use the contains() flux function now to filter values included in that array called sessionsExclude.
Flux query section:
|> filter(fn:(r) => contains(value: r["session"], set: ${sessionsExclude}))
Getting an error unexpected token for property key: INT ("102")'. Not sure why. Looks like flux tries to turn the values into Integers? The r["session"] is also a String (and the example in the docs also uses an array of Strings)...
Ended up doing it in two queries. Still confused about the Strings vs Integers, but casting the value as an Int and printing out the array of r["session"] within the query seems to work like this:
'|> filter(fn:(r) => not contains(value: int(v: r["session"]), set: [${sessionsExclude.join(",")}]))'
Added the "not" to exclude instead of retain the values matching the array...
I have a type ORM query that returns five columns. I just want the company column returned but I need to select all five columns to generate the correct response.
Is there a way to wrap my query in another select statement or transform the results to just get the company column I want?
See my code below:
This is what the query returns currently:
https://i.stack.imgur.com/MghEJ.png
I want it to return:
https://i.stack.imgur.com/qkXJK.png
const qb = createQueryBuilder(Entity, 'stats_table');
qb.select('stats_table.company', 'company');
qb.addSelect('stats_table.title', 'title');
qb.addSelect('city_code');
qb.addSelect('country_code');
qb.addSelect('SUM(count)', 'sum');
qb.where('city_code IS NOT NULL OR country_code IS NOT NULL');
qb.addGroupBy('company');
qb.addGroupBy('stats_table.title');
qb.addGroupBy('country_code');
qb.addGroupBy('city_code');
qb.addOrderBy('sum', 'DESC');
qb.addOrderBy('company');
qb.addOrderBy('title');
qb.limit(3);
qb.cache(true);
return qb.getRawMany();
};```
[1]: https://i.stack.imgur.com/MghEJ.png
[2]: https://i.stack.imgur.com/qkXJK.png
TypeORM didn't meet my criteria, so I'm not experienced with it, but as long as it doesn't cause problems with TypeORM, I see an easy SQL solution and an almost as easy TypeScript solution.
The SQL solution is to simply not select the undesired columns. SQL will allow you to use fields you did not select in WHERE, GROUP BY, and/or ORDER BY clauses, though obviously you'll need to use 'SUM(count)' instead of 'sum' for the order. I have encountered some ORMs that are not happy with this though.
The TS solution is to map the return from qb.getRawMany() so that you only have the field you're interested in. Assuming getRawMany() is returning an array of objects, that would look something like this:
getRawMany().map(companyRecord => {return {company: companyRecord.company}});
That may not be exactly correct, I've taken the day off precisely because I'm sick and my brain is fuzzy enough I was making too many stupid mistakes, but the concept should work even if the code itself doesn't.
EDIT: Also note that map returns a new array, it does not modify the existing array, so you would use this in place of the getRawMany() when assigning, not after the assignment.
I'm using an auto incremental session variable temporary column, to get some kind of sequence for a specific sort-order. The query looks something like this:
return ctx.select(
field("rowNumber"),
TABLE.ID
).from(/* Get an inner query here */)
.where(TABLE.ID.eq(someValue))
.orderBy(field("rowNumber").asc());
But, when I try to execute the above query, it returns the following error:
Unknown column 'TABLE.ID' in 'field list'
The only way I can make it work, is when TABLE.ID is passed as field("ID") inside ctx.select().
Is it so that JOOQ doesn't support specifying the column(s) using a combination of TableRecord and field("column")?
Turns out, it is possible to do so. Apparently, the improper aliasing might have had something to do with the issue. Solved it like this:
TABLE t = TABLE.as("t");
return ctx.select(
field("rowNumber"),
t.ID
).from(getInnerQuery().asTable("t"))
.where(t.ID.eq(someValue))
.orderBy(field("rowNumber").asc());
I've have 2 tables CampaignCoverage and Coverage
CampaignCoverage has a CoverageID column. Coverage has a column DateX.
Basically I've not specified in the code that CampaignCoverage.CoverageID = Coverage.ID like you would to in SQL. How does this work at all????!!!!
CampaignCoverageCollection campaignCoverages =
new Select()
.From(Tables.CampaignCoverage)
.InnerJoin(Tables.Coverage)
.Where(Coverage.DateXColumn).IsGreaterThan(ucDateStart.DateTime)
.And(Coverage.DateXColumn).IsLessThan(ucDateEnd.DateTime)
.And(CampaignCoverage.CampaignIDColumn).IsEqualTo(campaign.Id)
.ExecuteAsCollection<CampaignCoverageCollection>();
If you have not specified that CampaignCoverage.CoverageID is a foreign key to Coverage.ID (I think that is what you are trying to say), then getting rid of the join should do the trick. i.e. Remove
.InnerJoin(Tables.Coverage)
That said, you probably do want to make a CampaignCoverage.CoverageID a foreign key to Coverage.ID. After you do that, you can get rid of the IsEqualTo clause. i.e. Remove
.And(CampaignCoverage.CampaignIDColumn).IsEqualTo(campaign.Id)