I want to select the MIN() and MAX() of a column from a table. But instead of querying the database twice I'd like to solve this in just one query.
I know I could do this
my $col = $schema->result_source("Birthday")->get_column("birthdate");
my $min = $col->min();
my $max = $col->max();
But it would query the database twice.
The only other solution I found is quite ugly, by messing around with the select and as attributes to search(). For example
my $res = $rs->search({}, {
select => [ {min => "birthdate"}, {max => "birthdate"},
as => [qw/minBirthdate maxBirthdate/]
});
say $res->get_column("minBirthdate")->first() . " - " . $res->get_column("maxBirthdate")->first();
Which produces this - my wanted SQL
SELECT MIN(birthdate), MAX(birthdate) FROM birthdays;
Is there any more elegant way to get this done with DBIx::Class?
And to make it even cooler, is there a way to respect the inflation/deflation of the column?
You can use columns as a shortcut to combine select and as attributes as such:
my $res = $rs->search(undef, {
columns => [
{ minBirthdate => { min => "birthdate" } },
{ maxBirthdate => { max => "birthdate" } },
]
});
Or, if you prefer more control over the SQL, use string refs, which can help with more complex calculations:
my $res = $rs->search(undef, {
columns => [
{ minBirthdate => \"MIN(birthdate)" },
{ maxBirthdate => \"MAX(birthdate)" },
]
});
Now, if you really want to clean it up a bit, I highly recommend DBIx::Class::Helpers, which allows you to write it as such:
my $minmax = $rs->columns([
{minBirthdate=>\"MIN(birthdate)"},
{maxBirthdate=>\"MAX(birthdate)"},
])->hri->single;
say "$minmax->{minBirthdate} - $minmax->{maxBirthdate}";
Related
I am using sequelize (postgres) and I need to properly escape a query like this:
`
UPDATE "Pets"
SET "name" = CASE LOWER("name")
${input.pets
.map((pet) => `WHEN '${pet.name.toLowerCase()}' THEN '${pet.newName}'`)
.join('\n')}
ELSE "name"
END
WHERE LOWER("name") IN(${input.pets
.map((pet) => `'${pet.name.toLowerCase()}'`)
.join(',')});
`
Sample input.pets:
[{ name: "rocky", newName: "leo" }]
Does anyone have an idea how to achieve this with replacements?
I have found a thread on github which suggested something like this:
let data = [ [ 252456, 1, 55, '0' ],
[ 357083, 1, 56, '0' ],
[ 316493, 1, 57, '0' ] ];
db.query(
`INSERT INTO product (a, b) VALUES ${data.map(a => '(?)').join(',')};`,
{
replacements: data,
type: Sequelize.QueryTypes.INSERT
}
);
However, a 2d array is being used here not an array of objects. Is there a way to access individual properties from the array? When I try something like this
`
UPDATE "Pets"
SET "name" = CASE LOWER("name")
${input.pets
.map((_pet) => `WHEN ? THEN ?`)
.join('\n')}
ELSE "name"
END
WHERE LOWER("name") IN(${input.pets
.map((_pet) => `?`)
.join(',')});
`,
{ type: QueryTypes.UPDATE, replacements: input.pets },
The first ? turns out to be the whole object. Is there a way to access it's properties?
I also tried transforming input.pets into a 2d array but still couldn't get it to work as in example with insert above.
In advance thanks for your time
const names = input.pets.map((pet) => pet.name);
const newNames = input.pets.map((pet) => pet.newName);
`
UPDATE "Pets"
SET "name" = CASE LOWER("name")
${names.map((_) => `WHEN LOWER(:names) THEN :newNames`).join('\n')}
ELSE "name"
END
WHERE LOWER("name") IN(${names.map((_) => `LOWER(:names)`).join(',')});
`,
{ replacements: { names, newNames } },
This works. In cases like this it's better to work with simpler data structures. Another option I found is using sequelize.escape() built-in function, but it's not documented so I decided not to
EDIT:
After some testing, this works but for only one object in the input
If the input looks something like this:
[
{ name: "rocky", newName: "fafik" }
{ name: "asd", newName: "qwerty" }
]
Then in resut I get queries like this:
WHEN LOWER('rocky', 'asd') THEN 'fafik', 'qwerty'
WHEN LOWER('rocky', 'asd') THEN 'fafik', 'qwerty'
So it doesn't loop over arrays. Still the problem remains, how to access individual properties, whether from array or an object?
EDIT2: FINAL ANSWER
sequelize.query(
`
UPDATE "Pets"
SET "name" = CASE LOWER("name")
${input.pets.map(() => `WHEN ? THEN ?`).join('\n')}
ELSE "name"
END
WHERE LOWER("name") IN(?);
`,
{
replacements: [
...input.pets.flatMap((x) => [x.name.toLocaleLowerCase(), x.newName]),
input.pets.map((x) => x.name.toLocaleLowerCase()),
],
},
I am having multiple nested where conditions and want to generate them without too much code duplication with typeORM.
The SQL where condition should be something like this:
WHERE "Table"."id" = $1
AND
"Table"."notAvailable" IS NULL
AND
(
"Table"."date" > $2
OR
(
"Table"."date" = $2
AND
"Table"."myId" > $3
)
)
AND
(
"Table"."created" = $2
OR
"Table"."updated" = $4
)
AND
(
"Table"."text" ilike '%search%'
OR
"Table"."name" ilike '%search%'
)
But with the FindConditions it seems not to be possible to make them nested and so I have to use all possible combinations of AND in an FindConditions array. And it isn't possible to split it to .where() and .andWhere() cause andWhere can't use an Object Literal.
Is there another possibility to achieve this query with typeORM without using Raw SQL?
When using the queryBuilder I would recommend using Brackets
as stated in the Typeorm doc: https://typeorm.io/#/select-query-builder/adding-where-expression
You could do something like:
createQueryBuilder("user")
.where("user.registered = :registered", { registered: true })
.andWhere(new Brackets(qb => {
qb.where("user.firstName = :firstName", { firstName: "Timber" })
.orWhere("user.lastName = :lastName", { lastName: "Saw" })
}))
that will result with:
SELECT ...
FROM users user
WHERE user.registered = true
AND (user.firstName = 'Timber' OR user.lastName = 'Saw')
I think you are mixing 2 ways of retrieving entities from TypeORM, find from the repository and the query builder. The FindConditions are used in the find function. The andWhere function is use by the query builder. When building more complex queries it is generally better/easier to use the query builder.
Query builder
When using the query build you got much more freedom to make sure the query is what you need it to be. With the where you are free to add any SQL as you please:
const desiredEntity = await connection
.getRepository(User)
.createQueryBuilder("user")
.where("user.id = :id", { id: 1 })
.andWhere("user.date > :date OR (user.date = :date AND user.myId = :myId)",
{
date: specificCreatedAtDate,
myId: mysteryId,
})
.getOne();
Note that depending on your used database the actual SQL that you use here needs to be compatible. With that could also come a possible draw back of using this method. You will tie your project to a specific database. Make sure to read up about the aliases for tables you can set if you are using relations this would be handy.
Repository
You already saw that this is much less comfortable. This is because the find function or more specific the findOptions are using objects to build the where clause. This makes is harder to implement a proper interface to implement nested AND and OR clauses side by side. There for (I assume) they have chosen to split AND and OR clauses. This makes the interface much more declarative and means the you have to pull your OR clauses to the top:
const desiredEntity = await repository.find({
where: [{
id: id,
notAvailable: Not(IsNull()),
date: MoreThan(date)
},{
id: id,
notAvailable: Not(IsNull()),
date: date
myId: myId
}]
})
I cannot imagin looking a the size of the desired query that this code would be very performant.
Alternatively you could use the Raw find helper. This would require you to rewrite your clause per field, since you will only get access to the one alias at a time. You could guess the column names or aliases but this would be very poor practice and very unstable since you cannot directly control this easily.
if you want to nest andWhere statements if a condition is meet here is an example:
async getTasks(filterDto: GetTasksFilterDto, user: User): Promise<Task[]> {
const { status, search } = filterDto;
/* create a query using the query builder */
// task is what refer to the Task entity
const query = this.createQueryBuilder('task');
// only get the tasks that belong to the user
query.where('task.userId = :userId', { userId: user.id });
/* if status is defined then add a where clause to the query */
if (status) {
// :<variable-name> is a placeholder for the second object key value pair
query.andWhere('task.status = :status', { status });
}
/* if search is defined then add a where clause to the query */
if (search) {
query.andWhere(
/*
LIKE: find a similar match (doesn't have to be exact)
- https://www.w3schools.com/sql/sql_like.asp
Lower is a sql method
- https://www.w3schools.com/sql/func_sqlserver_lower.asp
* bug: search by pass where userId; fix: () whole addWhere statement
because andWhere stiches the where class together, add () to make andWhere with or and like into a single where statement
*/
'(LOWER(task.title) LIKE LOWER(:search) OR LOWER(task.description) LIKE LOWER(:search))',
// :search is like a param variable, and the search object is the key value pair. Both have to match
{ search: `%${search}%` },
);
}
/* execute the query
- getMany means that you are expecting an array of results
*/
let tasks;
try {
tasks = await query.getMany();
} catch (error) {
this.logger.error(
`Failed to get tasks for user "${
user.username
}", Filters: ${JSON.stringify(filterDto)}`,
error.stack,
);
throw new InternalServerErrorException();
}
return tasks;
}
I have a list of
{
date: specificCreatedAtDate,
userId: mysteryId
}
My solution is
.andWhere(
new Brackets((qb) => {
qb.where(
'userTable.date = :date0 AND userTable.type = :userId0',
{
date0: dates[0].date,
userId0: dates[0].type,
}
);
for (let i = 1; i < dates.length; i++) {
qb.orWhere(
`userTable.date = :date${i} AND userTable.userId = :userId${i}`,
{
[`date${i}`]: dates[i].date,
[`userId${i}`]: dates[i].userId,
}
);
}
})
)
That will produce something similar
const userEntity = await repository.find({
where: [{
userId: id0,
date: date0
},{
id: id1,
userId: date1
}
....
]
})
I'm having trouble getting the correct query with sequelize.
I have an array representing ids of entries lets say its like this -
userVacationsIds = [1,2,3]
i made the first query like this
Vacation.findAll({
where: {
id: {
[Op.or]: userVacationsIds
}
}
})
.then(vacationSpec => {
Vacation.findAll({
where:{
//Here i need to get all entries that DONT have the ids from the array
}
}
})
I can't get the correct query as specified in my code "comment"
I've tried referring to sequelize documentation but i can't understand how to chain these queries specifically
Also tried an online converter but that failed too.
Specified the code i have above
So i just need some help getting this query correct please.
I eventually expect to get 2 arrays - one containing all entries with the ids from the array, the other containing everything else (as in id is NOT in the array)
I figured it out.
I feel silly.
This is the query that worked
Vacation.findAll({
where: {
id: {
[Op.or]: userVacationsIds
}
}
}).then(vacationSpec => {
Vacation.findAll({
where: {
id: {
[Op.notIn]: userVacationsIds
}
}
})
I'm using Standard SQL with Big Query and everything is working fine, except my dates are in a nested structure and I have no idea why Big Query is doing that.
Here's my query:
SELECT
DATETIME(salesData.date_utc, "EST") AS DateEST,
salesData.serial_no AS MachineID
FROM
sales.sales_all AS salesData
WHERE salesData.date_utc > "2018-05-26T05:00:00" AND salesData.date_utc
< "2018-05-27T04:59:59"
ORDER BY salesData.date_utc DESC
When I'm downloading the results as JSON it's all fine:
{"DateEST":"2018-05-26T23:57:58","MachineID":"1708FB0000009-B"}
{"DateEST":"2018-05-26T23:52:07","MachineID":"1710FB0000034-B"}
But if I'm using Google Cloud Functions and pull the data, it results in a nested JSON.
[
{
"DateEST": {
"value": "2018-05-26T23:57:58"
},
"MachineID": "1708FB0000009-B"
}, ...
Here's part of my Cloud Function code:
const options = {
query: sqlQuery,
useLegacySql: false, // Use standard SQL syntax for queries.
};
bigquery
.query(options)
.then(results => {
const rows = results[0];
response.json(rows);
})
.catch(err => {
console.error('ERROR:', err);
response.send(500);
});
This issue was solved by casting the DATETIME object as a string:
CAST(DATETIME(salesData.date_utc, "EST") as STRING) as DateEST
With SQL we can do the following :
select * from x where concat(x.y ," ",x.z) like "%find m%"
when x.y = "find" and x.z = "me".
How do I do the same thing with MongoDB, When I use a JSON structure similar to this:
{
data:
[
{
id:1,
value : "find"
},
{
id:2,
value : "me"
}
]
}
The comparison to SQL here is not valid since no relational database has the same concept of embedded arrays that MongoDB has, and is provided in your example. You can only "concat" between "fields in a row" of a table. Basically not the same thing.
You can do this with the JavaScript evaluation of $where, which is not optimal, but it's a start. And you can add some extra "smarts" to the match as well with caution:
db.collection.find({
"$or": [
{ "data.value": /^f/ },
{ "data.value": /^m/ }
],
"$where": function() {
var items = [];
this.data.forEach(function(item) {
items.push(item.value);
});
var myString = items.join(" ");
if ( myString.match(/find m/) != null )
return 1;
}
})
So there you go. We optimized this a bit by taking the first characters from your "test string" in each word and compared the tokens to each element of the array in the document.
The next part "concatenates" the array elements into a string and then does a "regex" comparison ( same as "like" ) on the concatenated result to see if it matches. Where it does then the document is considered a match and returned.
Not optimal, but these are the options available to MongoDB on a structure like this. Perhaps the structure should be different. But you don't specify why you want this so we can't advise a better solution to what you want to achieve.