I want to retrieve a specific row from the database.
so I'm using this command to retrieve it :
UserOwner userowner =_context.User.FromSql("SELECT * FROM db.user WHERE name = 'username'").FirstOrDefault();
return Ok(user);
the thing is this returns a list and I return the first on the list, but isn't there a way to return straight from the SQL command one row?
try use labda function on FirstOrDefault.
UserOwner userowner =_context.User.FirstOrDefault(o=> o.name == "username" );
return Ok(user);
but if you need use an SQL script, for MYSQL use:
"SELECT * FROM db.user WHERE name = 'username' LIMIT 1"
If I'm understanding your question correctly, you can do this using a "with" clause to get all of the rows and add a counter/index column then add a where clause to get the specific row. This would give you the 5th row from the original query.
with mainqry as (select t.*, rownum as myindex from db.user t where t.name ='username') select * from mainqry q where q.myindex=5;
Related
i am having troubles understanding how to access columns from a subquery (MySQL). Here is my code:
Personne personne = Personne.PERSONNE.as("personne");
Evenement evenement = Evenement.EVENEMENT.as("evenement");
Genealogie genealogie = Genealogie.GENEALOGIE.as("genealogie");
Lieu lieu = Lieu.LIEU.as("lieu");
SelectField<?>[] select = { DSL.countDistinct(personne.ID).as("countRs"), lieu.LIBELLE.as("libelleRs"),
lieu.ID.as("idVille") };
Table<?> fromPersonne = evenement.innerJoin(personne).on(personne.ID.eq(evenement.IDPERS))
.innerJoin(genealogie).on(genealogie.ID.eq(personne.IDGEN)).innerJoin(lieu)
.on(lieu.ID.eq(evenement.IDLIEU));
Table<?> fromFamille = evenement.innerJoin(personne).on(personne.IDFAM.eq(evenement.IDFAM))
.innerJoin(genealogie).on(genealogie.ID.eq(personne.IDGEN)).innerJoin(lieu)
.on(lieu.ID.eq(evenement.IDLIEU));
GroupField[] groupBy = { lieu.ID };
Condition condition = //conditionally build, not relevant i think
result = create.select(DSL.asterisk())
.from(create.select(select).from(fromPersonne).where(condition).groupBy(groupBy)
.union(create.select(select).from(fromFamille).where(condition).groupBy(groupBy)))
// i would like something like this but i don't know how: .groupBy(groupBy).fetch();
Basicly what i have is:
SELECT
*
FROM(
(SELECT
countRs, libelleRs, idVille
FROM
fromPersonne
WHERE
-- conditions
GROUP BY lieu.ID)
UNION
(SELECT
countRs, libelleRs, idVille
FROM
fromFamille
WHERE
-- conditions
GROUP BY lieu.ID)
)GROUP BY lieu.ID -- this is where i need help
In a plain MySQL query i would just give an alias to the union and then make a reference to the column i want to group by using the alias but it seems like it does not work like this with JOOQ.
I just need to group the results of the subqueries together but i don't know how to make a reference to the subqueries columns... I am sure i would have to reference my subqueries in objects outside of that "main select" to be able to access the columns or something along those lines but i am lost in all the object types.
You have to assign your derived table to a local variable and dereference columns from it, e.g.
Table<?> t = table(
select(...).from(...).groupBy(...).unionAll(select(...).from(...).groupBy(...))
).as("t");
Field<Integer> tId = t.field(lieu.ID);
I use Sphinx with Yii2 and need to query with filter by jSON field.
$query = new \yii\sphinx\Query();
$query->from('announcements');
$query->addSelect("*");
$query->addSelect(new Expression("IN(filters['color'], 'blue', 'red', 'green') AS f_color"));
$query->where("is_active = 1");
$query->andWhere("f_color = 1");
$announces = $query->all();
There is jSON field filters in my Sphinx index. For example:
[filters] => {"brand":"Toyota","model":"Prius","color":"red","price":"12000"... etc]
It works OK. But now I need to make a pagination... and there is a problem when I try to count records before $query->all()
$count = $query->count(); // Return error "no such filter attribute 'f_color'"
Generated query was:
SELECT COUNT(*) FROM announcements WHERE ( is_active = 1 ) AND ( f_color = 1 )
count() by default replaces the select part with * and this is where your alias is defined hence the error.
There are different ways to achieve it like:
use ActiveDataProvider like described here,
use META information like described here
Since you want to make a pagination I would go with the first example.
I have a sql statement follow:
select * from table where id = ?
Now, problem is, l don't know whether front end will send me the value of id, if it did, this sql seem like id = 1, and if not, sql should be like id = true(fake code) to find all data
How could I write my sql?
Or, It is fundamentally wrong?
This is normally handled by using logic such as this:
select *
from table
where id = ? or ? is null;
If you don't want to pass the parameter twice or use named parameters:
select t.*
from table t cross join
(select ? as param) params
where id = params.param or params.param is null;
If you want to return all ids if the passed-in value does not exist:
select t.*
from table t
where id = ? or
not exists (select 1 from table t2 where t2.id = ?);
What you can try doing is in your code, write a function for fetching a specific record, and another function for fetching all the records from your table.
In PHP, it could be something like:
// Fetching a specific record
function getCustomerRecord($customerId) {
// Code to fetch specific record from database
}
// Fetching all records
function getAllCustomerRecords() {
// Code to fetch all records from database
}
In the function where you process requests received, check first if a value for id was passed. If a value for id was passed, call the function to fetch a specific record, making sure to pass along the value you received as an argument. Otherwise, call the function to fetch all the records from your table.
You can try doing this to get your right sql statement in PHP
function GetSqlStatement($id){
return $sql = "select * from table where id = ".$id.";";
}
[major edit to make things clear]
I want to write a query that returns a dynamic column name like this:
SELECT
f2 AS
(
SELECT column_name
FROM column_names_tbl
WHERE column_name = "experience"
limit 0,1
)
FROM some_table
so that would output the same as this:
SELECT
f2 AS experience
FROM some_table
This is no correct SQL syntax, even because the two queries (the selected field and it's alias) are both subqueries and unrelated to each other. So, there's also no possibility for mysql to distinguish what name you want to connect to what value, even if the syntax was correct...
You already use a more or less normalized relational table, so I suggest the following solution:
you select the revision ID and name in a separate query; store them in PHP and use them for whatever you want
next, you evaluate the following query into a separated result set: SELECT ps.keyname, psv.keyvalue FROM page_setting_values AS psv INNER JOIN page_settings AS ps ON ps.id = psv.setting_id WHERE psv.page_revision_id = :revision with :revision representing your revision id
you may now assemble an associated array from that result set:
$settings = [];
$result = $db->executeQuery('...')->fetchAll();
foreach($result as $setting)
{
$settings[$setting['keyname']] = $setting['keyvalue'];
}
Hope that helps ;)
I want to count how many records from another table in the same select statement , i used Left join
and in the select statement i put count(ag.*)
see the
Example :
$q = Doctrine_Query::create()
->select("a.answer_id,a.date_added , count(ag.content_id) AS agree_count")
->from('Answer a')
->leftJoin("a.Agree ag ON a.answer_id = ag.content_id AND ag.content_type = 'answer' ")
->where('a.question_id= ? ', $questionId)
But its only returning the first record, can i Fix that? or to make another table and make it only for counting ?
You are missing a GROUP BY in your query.
More infos here.
When you don't have a GROUP BY clause, it's normal to get only one row.
Count(*) will only return one record if you don't use Group By. You are asking it to count all the records, so there can be only one result.
The count() SQL function changes how results are returned from the database - without a GROUP BY the database will only return one record, regardless of other colums in the SELECT.
if you add:
group by a.answer_id
to the end of your SQL query, that might DWYM.