I am forced to use raw query with the Knex, since there is an issue with the union
One query, is not that bad. But now I have other type of issue.
All other Knex queries (non raw ones), they simply return an array with the results
For example:
knex('user_subscription_plan')
.select('*')
.where('paused_days', '>', 91)
.where('status', 'N_PAUSED')
will return an array, empty of there is no results.
However, if I run raw query, for example:
mySqlClient.raw('select * from user')
it will return an array, with two arrays inside it.
First one is the normal result, while other one contains some catalogue definitions.
That interferes with my logic. At the end of each call to knex, I have:
if (result.length > 0) {
// send email
}
Now, when I run the raw Query, the result is always greater then zero.
How can I tell Knex not to send the catalogue definitions, in other words, just send results back, exactly like it does on non raw queries?
According to https://github.com/knex/knex/issues/1802 there is no way around it, just do
mySqlClient.raw('select * from user')[0]
You should do it like #horatiu-jeflea answered.
Though we could add some way to knex to tell that also result of raw query should be parsed with default result parser. To make that way to appear in knex you could open feature request to its github issues.
Also there is https://knexjs.org/#Installation-post-process-response which you should be able to override to handle your raw query results are post processed.
If you want to get the same result as the select result, use select and pass your raw query as an argument without "SELECT" keyword. In your example, instead of doing:
mySqlClient.raw('select * from user')
You should do:
mySqlClient.select( mySqlClient.raw(' * from user') )
Related
Setup:
I'm using Ruby on Rails with ActiveRecord and MySQL.
I have a Coupon model.
It has an attribute called query, it is a string which could be run with a where.
For example:
#coupon.query
=> "'http://localhost:3003/hats' = :url OR 'http://localhost:3003/shoes' = :url"`
If I were to run this query it would either pass or fail based on the :url value I pass in.
# passes
Coupon.where(#coupon.query, url: 'http://localhost:3003/hats')
Coupon.where(#coupon.query, url: 'http://localhost:3003/shoes')
# fails
Coupon.where(#coupon.query, url: 'http://localhost:3003/some_other_url')
This query varies between Coupon models, but it will always be compared to the current url.
I need a way to say: Given an ActiveRecord collection #coupons only keep coupons with queries that pass.
The structure of the where is always the same, but the query changes.
Is there any way to do this without a loop? I could potentially have a lot of coupons and I am hoping to do this an ActiveRecord scope. Something like this?
#coupons.where(self.query, url: #url)
Perhaps I need to write a user defined function in my database?
Using multiple variables in a query is easy, but where the thing you are comparing your variable to is also a variable - that has me stumped. Any suggestions very appreciated.
I would agree with Les Nightingill's comment that this looks like something that should probably be solved at a more architectural level. I'd imagine an easy refactoring to extract a new CouponQuery model that's a 1:n table containing multiple entries for a coupon_id for each query url that should pass. Then you could use a simple join like
Coupon.joins(:coupon_query).where(coupon_queries: { url: my_url })
If adding a new table is not an option, and if you're running on a newer MySQL version (>= 5.7), you could consider transforming the query column (or adding a new json_query column) into a MySQL JSON field and using the new JSON_CONTAINS query.
If from the user-side they should be able to manage the queries as a plain text field, you could use a before_save hook on your model to translate this into the separate table structure or JSON format respectively.
But if neither is an option for you and you really need to stick with the query column that stores a plain string, then you could use a LIKE query to match the sub-string 'your-url' = :url:
Coupon.where('url LIKE "%? = :url%"', my_url)
which, if you e.g. pass 'http://localhost:3003/hats' as my_url would return something like this SQL query:
SELECT `coupons`.* FROM `coupons`
WHERE (url LIKE "%'http://localhost:3003/hats' = :url%")
So, I am trying to execute a query using ArcGIS API, but it should match any Json queries. I am kind of new to this query format, so I am pretty sure I must be missing something, but I can't figure out what it is.
This page allows for testing queries on the database before I actually implement them in my code. Features in this database have several fields, including OBJECTID and Identificatie. I would like to, for example, select the feature where Identificatie = 1. If I enter this in the Where field though (Identificatie = 1) an error Failed to execute appears. This happens for every field, except for OBJECTID. Querying where OBJECTID = 1 returns the correct results. I am obviously doing something wrong, but I don't get it why OBJECTID does work here. A brief explanation (or a link to a page documenting queries for JSON, which I haven't found), would be appreciated!
Identificatie, along with most other fields in the service you're using, is a string field. Therefore, you need to use single quotes in your WHERE clause:
Identificatie = '1'
Or to get one that actually exists:
Identificatie = '1714100000729432'
OBJECTID = 1 works without quotes because it's a numeric field.
Here's a link to the correct query. And here's a link to the query with all output fields included.
Is it possible to create a generic query that would work for different types of documents? For example I have "cases" and "factories",
They have different set of fields. e.g:
{
id: 'case_o1',
name: 'Case numero uno',
amount: 40
}
{
id: 'factory_002',
location: 'Venezuela',
workers: 200,
operating: true
}
Is it possible to create a generic query where I would pass the type of an entity (case or factory) and additional parameters and it would filter results based on those?
I could of course use javascript view, but it doesn't allow me to filter by multiple fields. Let's say I want to fetch all factories located in Venezuela, with number of workers between 20 and 55.
I started with this, but then I got stuck:
select * from `mybucket` as entity
where position(meta(entity).id, $entity_type) == 0
How do I pass multiple predicates and have the query to recognize them?
I can of course list fields like this:
where position(meta(entity).id, $entity_type) == 0
and entity.location == 'Venezuela'
and entity.workers > $workers_min
and entity.workers < $workers_max
but then
I'm gonna have to create a separate query for each entity
And even then it won't solve my problem - I have no idea how to ignore predicates, what if next time $workers_min and $workers_max are not passed, does it mean I have to create a query for every single predicate (column)?
For security reasons I cannot generate free-form queries and pass them to Couchbase server, all the queries are already stored in the database, our api just picks them up out of a document and executes them
I think it's possible to create a query that would be "short-circuiting" for args that's undefined (e.g. WHERE $location IS MISSING OR entity.location == $location or something like that)
Is it possible at all to create a query that would be able to effectively filter and order a dataset based on arbitrary parameters? Or there's no way?
#Agzam. Sorry. I were writting my comment when you said it. But anyway. What you are asking for is possible by using coalesces in a not too complex expressions, but it is a REALLY bad idea because this will drastically throw down most of internal database optimizations. Including the use of any existing index. So, except if you are dealing with a relatively small database (and you are sure it will remain being approximately the same size), I suggest you to better try distinct approach… This is, in fact, the reason I implmented sqlapi.
If you need to have all querys previously stored in database, it probably could be much better to sort given arguments by its name and precalculate and store precalculated querys for each possible combination.
You can do it by assigning a default value to the variable when is not used. For instance if $location is not used you can set it to -1 as default value.
Then the where condition would be:
WHERE ($location=-1 OR entity.location = $location)
I am using lua script
https://github.com/clofresh/mysql-proxy-cache to cache the select query.
But there is a problem with the way it is detecting select statement.
It is using following code
return query:sub(1,6):lower() == 'select'
This will not work if select query is nested in (). Example:
(SELECT * from tbl_name);
Is there a way to remove extra () in mysql proxy ?
or Is there a better way to detect select query?
I would try to write a normalizing script using the String Library that detect common patterns and replaces them with equivalent normalized sql.
One example is your parenteses but also queries where the where parts have been moved around could benefit from this.
The queries are actually inside of the the parentheses, not inside of a string? That shouldn't parse correctly, even with a plug in. If it is in a string then simply use :sub(2, 7), however, if it is not, then put it inside of a string. Create a function that basically reproduces the function, except puts it in a string, e.g.:
function mysqlQuery(mysqlString)
loadstring(mysqlString)();
return mysqlString;
end
mysqlQuery("SELECT * from tbl");
I have a fairly complex query (that includes a table valued function to allow full text searching) that I am trying to cache (HttpRuntime.Cache) for paging purposes. When I try to use the cached L2S query, I get the error stated above: The query results cannot be enumerated more than once.
I have tried assigning my query to another IQueryable object by calling AsIQueryable() on the cached object, but that does not help.
Any ideas?
You could store the results of the query in the cache instead of the query itself by calling .ToArray() or .ToList() extension methods which will execute the query immediately. Then you can enumerate the results from the cache as much as you wish.
use
var retVal = (.....).First() or ToList();
and use retVal.Name, retVal.Surname ....
if you use ToList();, you need to give an index like retVal[1].Name