Note: this is a similar but NOT duplicate question with How to use sqlx to query mysql IN a slice?. I'm asking for the Rust one.
This is what I try to do.
let v = vec![..];
sqlx::query("SELECT something FROM table WHERE column IN (?)").bind(v)
...
Then I got the following error
the trait bound `std::vec::Vec<u64>: sqlx::Encode<'_, _>` is not satisfied
Answer is in first on FAQ https://github.com/launchbadge/sqlx/blob/master/FAQ.md
How can I do a SELECT ... WHERE foo IN (...) query? In 0.6 SQLx will
support binding arrays as a comma-separated list for every database,
but unfortunately there's no general solution for that currently in
SQLx itself. You would need to manually generate the query, at which
point it cannot be used with the macros.
The error shows Vec is not an Encode that is required to be as a valid DB value. The Encode doc lists all the Rust types that have implemented the trait. Vec is not one.
You can use the following way to bind the parameters in IN with the values of a vector. Firstly, you need to expand the number of '?' in the IN expression to be the same number of the parameters. Then, you need to call bind to bind the values one by one.
let v = vec![1, 2];
let params = format!("?{}", ", ?".repeat(v.len()-1));
let query_str = format!("SELECT id FROM test_table WHERE id IN ( { } )", params);
let mut query = sqlx::query(&query_str);
for i in v {
query = query.bind(i);
}
let row = query.fetch_all(&pool).await?;
Please note if the target database is not MySql, you need to use $n, like $1, $2, instead of ?, as the parameter placeholder.
Related
I'm Using Scala(2.11) and playframework(2.3) and trying to run a query using a helper function to get results through pattern matching. The function is as follows
def resultsfunc() = {
val gradeRegex = "^Class 5\."
val currRegex = "\.NCERT$"
DB.withConnection{ implicit c =>
val filterQuery = SQL(
"""
select * from tbl_graphs
where graph_name REGEXP '{grade_regex}' and
graph_name REGEXP '{curr_regex}' and org_id = 4
""")
.on("grade_regex" -> gradeRegex,
"curr_regex" -> currRegex)
filterQuery().map{ graphRecord =>
new ResultObj(graphRecord[Long]("id"),
graphRecord[String]("name"))
}.toList
}
}
I don't get any errors but I get empty result even though there are multiple records that match the pattern. The same query works if I try to run in mysql workbench and when I tried to print filterQuery the arguments were also mapped correctly.
Should Pattern matching with regex must be carried out differently in Scala Anorm ?
It has absolutely nothing to do specifically with Anorm.
Make sure that executing manually the query with exactly the same data and parameter, you get result.
When using JDBC (even through Anorm), string parameter must not be quoted in the query statement (... '{grade_regex}' ...).
Since a long time, it's recommended to use Anorm interpolation (SQL"SELECT x FROM y WHERE z = ${v}") rather than SQL(..) function.
I've been stuck on a GORM issue for about a full day now. I need to be able to filter a messages table on any of 4 things: sender, recipient, keyword, and date range. It also has to paginate. Filtering by sender and recipient is working, and so is pagination. So far this is the query that I have come up with, but it does not seem to work for date ranges or keywords.
Here is how I am selecting from MySQL
db.Preload("Thread").Where(query).Scopes(Paginate(r)).Find(&threadMessages)
I am creating the query like this:
var query map[string]interface{}
Then based on which parameters I am passed, I update the query like this by adding new key values to the map:
query = map[string]interface{}{"user_id": sender, "recipient_id": recipient}
For dates it does not seem to work if I try something like this:
query = map[string]interface{}{"created_at > ?": fromDate}
And for a LIKE condition is also does not seem to work:
query = map[string]interface{}{"contents LIKE ?": keyword}
The reason I chose this approach is that I could not seem to get optional inputs to work in .Where since it takes a string with positional parameters and null positional parameters seem to cause MySQL to return an empty array. Has anyone else dealt with a complicated GORM issue like this? Any help is appreciated at this point.
Passing the map[string]interface{} into Where() only appears to work for Equals operations, or IN operations (if a slice is provided as the value instead).
One way to achieve what you want, is to construct a slice of clause.Expression, and append clauses to the slice when you need to. Then, you can simply pass in all of the clauses (using the ... operator to pass in the whole slice) into db.Clauses().
clauses := make([]clause.Expression, 0)
if mustFilterCreatedAt {
clauses = append(clauses, clause.Gt{Column: "created_at", fromDate})
}
if mustFilterContents {
clauses = append(clauses, clause.Like{Column: "contents", Value: keyword})
}
db.Preload("Thread").Clauses(clauses...).Scopes(Paginate(r)).Find(&threadMessages)
Note: If you're trying to search for content that contains keyword, then you should concatenate the wildcard % onto the ends of keyword, otherwise LIKE behaves essentially the same as =:
clause.Like{Column: "contents", Value: "%" + keyword + "%"}
My final solution to this was to create dynamic Where clauses based on which query params were sent from the client like this:
fields := []string{""}
values := []interface{}{}
If, for example, there is a keyword param:
fields = []string{"thread_messages.contents LIKE ?"}
values = []interface{}{"%" + keyword + "%"}
And to use the dynamic clauses in the below query:
db.Preload("Thread", "agency_id = ?", agencyID).Preload("Thread.ThreadUsers", "agency_id = ?", agencyID).Joins("JOIN threads on thread_messages.thread_id = threads.id").Where("threads.agency_id = ?", agencyID).Where(strings.Join(fields, " AND "), values...).Scopes(PaginateMessages(r)).Find(&threadMessages)
Hi I'm currently trying to query records from db and these are the conditions
I receive 'order by', 'order (desc/asc)', 'limit', 'offset' from the frontend
I also need to search the record using match...against. 'like' is too slow for searching.
There's a mapped model with this query.
so I tried
let order_by = req.query.orderby;
let order = req.query.order;
let page = req.query.pagenum;
let perpage = req.query.parpage;
let searchword = req.query.foodsearch;
let offset = (parseInt(page) - 1) * parpage;
let foods = await models.food.findAll({
limit: parseInt(perpage),
offset: offset,
order: [
[order_by, order]
],
// where: Sequelize.literal
// (
// `MATCH
// (Name, Place, RestoNum, Ingredient, ChefName, Region...)
// AGAINST
// ( ? IN NATURAL LANGUAGE MODE)`,
// { replacements: [ searchword ] }
// )
});
but the commented part seems wrong in this code.
I tried the raw query, but then I can't parameterize those order by, order, offset, limit variables.
I don't want to just add them like ${orderby} because it's risky.
Please let me know if you have any solution for this issue.
Thank you in advance!
You're confusing the Sequelize.literal() and sequelizeInstance.query() APIs.
.literal() only take a string. If you want to use the object notation for your query, your commented code will work. Except that there is no second argument. You will need to concatenate-in or interpolate-in your search term into the AGAINST clause. Also, don't forget your quotes. The output of the literal() is essentially a string. Your MySQL FTS parameter will need the correct type of quotes around it, just as they would appear in your raw SQL query.
.query() DOES take an options parameter. Through this, you don't have to use string interpolation, you can use named replacements or bound-parameters. This will not only allow you to place in your searchword parameter, but whatever ORDER BY clause you want, as well.
I would go with Option 1. That's what we are doing for our FTS, in MS SQL.
I have data loaded from JSON and am trying to extract arbitrary nested values using a list as input, where the list corresponds to the names of successive children. I want a function get_value(data,lookup) that returns the value from data by treating each entry in lookup as a nested child.
In the example below, when lookup=['alldata','TimeSeries','rates'], the return value should be [1.3241,1.3233].
json_data = {'alldata':{'name':'CAD/USD','TimeSeries':{'dates':['2018-01-01','2018-01-02'],'rates':[1.3241,1.3233]}}}
def get_value(data,lookup):
res = data
for item in lookup:
res = res[item]
return res
lookup = ['alldata','TimeSeries','rates']
get_value(json_data,lookup)
My example works, but there are two problems:
It's inefficient - In my for loop, I copy the whole TimeSeries object to res, only to then replace it with the rates list. As #Andrej Kesely explained, res is a reference at each iteration, so data isn't being copied.
It's not concise - I was hoping to be able to find a concise (eg one or two line) way of extracting the data using something like list comprehension syntax
If you want one-liner and you are using Python 3.8, you can use assignment expression ("walrus operator"):
json_data = {'alldata':{'name':'CAD/USD','TimeSeries':{'dates':['2018-01-01','2018-01-02'],'rates':[1.3241,1.3233]}}}
def get_value(data,lookup):
return [data:=data[item] for item in lookup][-1]
lookup = ['alldata','TimeSeries','rates']
print( get_value(json_data,lookup) )
Prints:
[1.3241, 1.3233]
I don't think you can do it without a loop, but you could use a reducer here to increase readability.
functools.reduce(dict.get, lookup, json_data)
I have a lua script, which simplified is like this:
local item = {};
local id = redis.call("INCR", "counter");
item["id"] = id;
item["data"] = KEYS[1]
redis.call("SET", "item:" .. id, cjson.encode(item));
return cjson.encode(item);
KEYS[1] is a stringified json object:
JSON.stringify({name : 'some name'});
What happens is that because I'm using cjson.encode to add the item to the set, it seems to be getting stringified twice, so the result is:
{"id":20,"data":"{\"name\":\"some name\"}"}
Is there a better way to be handling this?
First, regardless your question, you're using KEYS the wrong way and your script isn't written according to the guidelines. You should not generate key names in your script (i.e. call SET with "item:" .. id as a keyname) but rather use the KEYS input array to declare any keys involved a priori.
Secondly, instead of passing the stringified string with KEYS, use the ARGV input array.
Thirdly, you can do item["data"] = json.decode(ARGV[1]) to avoid the double encoding.
Lastly, perhaps you should learn about Redis' Hash data type - it may be more suitable to your needs.