I've been having some issues with a query. I'm trying to get the most recent record for each 'category' from a table, but I can't figure out how to write the query in Laravel.
I got the query working in MySQL, but no real luck in translating it.
The MySQL query looks like this:
SELECT *
FROM messages
WHERE id IN (
SELECT MAX(id)
FROM messages
GROUP BY conversation_id
);
I was trying something like this in Laravel, but it doesn't seem to work:
return self::where(function($query){
$query->select(max(['id']))
->from('messages')
->groupBy('conversation_id');
})
->get();
(Posted on behalf of the OP).
Thanks to AlexM's comments I figured it out.
return self::whereIn('id', function($query){
$query->select(max(['id']))
->from('messages')
->orderBy('created_at', 'desc')
->groupBy('conversation_id');
})
->get();
Was my first solution but that didn't work quite well. It was selecting two records as intended, but not the last ones.
I've then come up with the idea to use selectRaw instead select, which solved my issue perfectly. The final query looks like this, for any interested:
return self::whereIn('id', function($query){
$query->selectRaw('max(id)')
->from('messages')
->orderBy('created_at', 'desc')
->groupBy('conversation_id');
})
->get();
Related
I am having issues with laravel eloquent join to compare date in where clause using sub query. below query gives me error unknown column policy_periods.statecode i am using this column in where clause of the join subquery for example App\Elrd::where("state_code",'=',DB::raw(policy_periods.statecode))->where('date',"<=",$mod_rating_eff_date)->max('date')
can you please give me an idea if any solution possible ?
i have already tried whereRaw, whereColumn but none of them is working.
DB::table('policy_periods')
->join('payrolls','payrolls.policy_period_id', '=', 'policy_periods.id')
->leftjoin('elrds', function($join) use($mod_rating_eff_date)
{
$join->on('elrds.state_code', '=', 'policy_periods.statecode');
$join->on('elrds.class_code', '=', 'payrolls.code');
$join->where('elrds.date',App\Elrd::where("state_code",'=',DB::raw(`policy_periods`.`statecode`))->where('date',"<=",$mod_rating_eff_date)->max('date'));
})
->select('payrolls.*','payrolls.elr as payrollelr','policy_periods.id as pid','policy_periods.policy_no',DB::raw('CONCAT(eff_date, "-", exp_date) as dateGroup'),'policy_periods.eff_date','policy_periods.exp_date','policy_periods.statecode as ratingeffPolicyYear','policy_periods.statecode','elrds.class_code','elrds.year','elrds.date','elrds.elr','elrds.dratio')
->where('policy_periods.mod_id',$id)
->get();
When I encounter such issue, the first thing I usually do is to determine if the generated query is what I wanted.
You should log your queries so that you can ensure it.
To do that, a possible solution is to add a log in your AppServiceProvider (in function boot):
DB::listen(function ($query) {
Log::debug('query',[
$query->sql,
$query->bindings,
$query->time
]);
});
That being said, where do these backticks come from?
DB::raw(`policy_periods`.`statecode`)
You could replace it with DB::raw('policy_periods.statecode')
Please tell me if it fixes your issue, or provide the generated SQL query if the problem is not fixed.
I perform the following query with no problem. But it doesn't get the results I want.
I want 3 comments for each post, but I think it gets 3 comments totally. How can I resolve this?
$posts = Post::with([
'comments' => function($c) {
$c->orderBy('commentTimestamp', 'desc')->take(3)->get();
}
])
->take(10)
->get();
Your query is totally valid, I just ran it myself and got the right results, please check your database, if you do SELECT * FROM comments do you get records?
I have 100k record in my posts table and 100k records in users table.
When i use laravel's pagination. it takes too long to return data...!
Code:
$posts = Post::join('users', 'posts.user_id', 'users.id')
->where('posts.status', '=', 1)
->where('users.status', '=', 1)
->paginate(10);
How can i fix this and got better performance?
Note
I have this problem also when i use inRandomOrder() on $posts
You can use Laravel simplePaginate() method.
It will show only "Next" and "Previous" links, if that is enough for you.
https://laravel.com/docs/5.0/pagination#usage
I'm trying to get the most recent record for each candidate_id from a ìnterviews` table.
This is what I want to achive:
I'm using Eloquent on laravel and have already tried this methods (with and without eloquent):
$candidates = DB::table('interviews')->select('interviews.*', 'i2.*')
->leftJoin('interviews as i2',
function ($join) {
$join->on('interviews.candidate_id', '=', 'i2.candidate_id');
$join->on('interviews.created_at', '<', 'i2.created_at');
}
)
->whereNull('i2.candidate_id')
->get();
and with eloquent I've tried this:
$candidates = Interview::leftJoin('interviews as i2',
function ($join) {
$join->on('interviews.candidate_id', '=', 'i2.candidate_id');
$join->on('interviews.created_at', '<', 'i2.created_at');
}
)->whereNull('i2.candidate_id')
->get();
If I change get() to toSql() I have exactly the same query that's shown on the above image, but running on laravel I'm getting always these results (this using the first method, with query builder):
Anyone know why I get this results? Is hard to understand that laravel is doing the same query that I do in HeidiSql but I get diferent results :(
Any tip?
Thanks in advance!
Because you are using ->select('interviews.*', 'i2.*') combined with ->whereNull('i2.candidate_id') I am assuming the second select parameter is overriding all fields on the interviews table with nulls, try reversing the order to ->select('i2.*','interviews.*') or not use the i2.* at all.
This is because the output ignores the alias and only uses the fieldname as element key in the returned collection.
Hope it works.
Perfect case scenario you pick the exact columns you want from each of the joined tables for e.g. it may go like this: table1.id,table1.column1,table1.column2,table2.column2 as smth_so_it_doesnt_override
I have an laravel eloquent select statement which looks like this:
$test = Test::with(['a.b.companies']) .. and so on
Now, I want to return results for this query based on some company names in companies table.
I tried to write a where clause with various trial and errors but it doesn't work. I am new to laravel and mysql. Any help in the right direction will be good. thanks.
You may use where, for more reference : - Eloquent ORM
$test = Test::where('company_name1', '=', $company_name1)->orWhere('company_name2', '=', $company_name2)->get();