I have a variable $id = $request->id, which stores a particular id.
I want to fetch data from the database according to this id, and also get data for id values lower than it in reverse order.
For example, suppose I passed an id value of 5.
I want to fetch 5,4,3,2,1 id's data from the database.
How can I do this when using something like an employee table?
So if you pass it a value, you want it to retrieve all entries from the table which match that value or lower? In that case it's just a simple where clause (https://laravel.com/docs/8.x/queries#where-clauses) assuming you have an Employee model which is tied to that table :
$employees = Employee::where('id', '<=', $request->id)->get();
If $request->id is 10, this will get all employees with an ID equal to or lower than 10.
Related
I've taken over a project where they stored the date_start value in a JSON column.
(e.g, id, name, some_column, meta)
where in meta has a value of { propert1, property2, property3, "date_start": "2021-09-26", and so on...}
Now, in the front-end, I have to make a search feature, where I select a date.
Now in the back-end, since the value of date_start has been stored in a json column, I'd assume that I need to fetch all records first, loop through them and then decode the meta field.
Isn't it OVERALL bad? Or is there any other way?
Modern versions of database often support JSON column types. These json columns can be queried using SQL.
preferences column in users table:
{"dining": {"meal": "salad", "time": "20:00"}}
Query:
$users = DB::table('users')
->where('preferences->dining->meal', 'salad')
->get();
Checkout the Laravel docs on JSON Where clauses:
I want to select distinct results from one table, the structure is following:
id, user_id, category_id, last_answered_question_id
I have relation for last_answered_question_id called: lastAnsweredQuestion()
My query is:
Answer::select('category_id')->where(['user_id' => $userId])->distinct()->get();
This query works as expected but in this case I can't call relation $answer = lastAnsweredQuestion.
Is there any known way to get distinct items and call relation lastAnsweredQuestion() anyway?
I have a model User that has many Orders. Orders have many products, with the pivot table order-product. I don't want to preload and iterate through the orders if at all possible.
I need to return users where
signed_date === true on User
order_date on Order is after signed_date on User
order-product shows product hasn't been paid
I am failing on number 2.
In the following code, the first query within whereHas is wrong. I don't know how to reference the signed date of the user from within the where has. If I was iterating through users in a collection I could do something like ($query) use $user, but how do I do this without preloading all the users?
return User::whereNotNull('signed_date')
->whereHas('orders', function ($query) {
$query->where('order_date', '<=', 'user.signed_date');
$query->whereHas('products', function ($q) {
$q->where('paid', false);
});
})
->get(['id','fname','lname', 'title', 'signed_date']);
I would like to use eloquent if possible. If that is not possible, I would be happy for tips in solving this problem using the query builder/sql.
The Eloquent query builder has a special function called whereColumn('a', '<=', 'b') to compare columns instead of a column against a value. Using this function instead of a normal where() is necessary because of the way the query builder builds the actual query. You need to let the query builder know that you are going to pass a column name instead of a value for proper escaping and formatting of the query string.
Anyway, it seems you can also pass column names prefixed with a table name to the function, allowing you to compare columns across tables:
$query->whereColumn('orders.order_date', '<=', 'users.signed_date')
This works because you are using whereHas() in your query. Your query basically gets translated to:
SELECT id, fname, lname, title, signed_date
FROM users
WHERE signed_date NOT NULL
AND EXISTS (
SELECT 1
FROM orders
WHERE orders.order_date <= users.signed_date
AND EXISTS (
SELECT 1
FROM products
WHERE paid = 0
)
)
It might actually be not necessary at all to use the table name together with the column name in whereColumn(). But in case you'll ever add a column named the same on another table, the query might break - so IMHO it is good practice to use the table name in custom queries.
By the way, the reason this will not work together with with('relationship') is that this function results in an additional query and you obviously cannot compare columns across queries. Imagine the following:
Order::with('user')->take(5)->get();
It will be translated into the following:
SELECT *
FROM orders
LIMIT 5
SELECT *
FROM users
WHERE id IN (?, ?, ?, ?, ?)
where the five ? will be the user_ids of the orders. If the first query returns multiple rows with the same user_id, the amount of rows fetched from the users table gets reduced of course.
Note: All the queries are only examples. Might be that the query builder builds different queries based on the database type and/or escapes them differently (i.e. column names in backticks).
Following is my query
$user = User::select(['uuid','name','about'])->with(['education','work'])->first();
this returns empty data for relationship education and work,
but if I remove select function from query I am getting data in relationship and it also returns all columns of user table which I don't want.
how can solve this problem
The problem is that relationships (with(...)) execute an additional query to get the related results. Let's say you have one to many relationship where users have many works. User::with('work')->find(1) will then execute these 2 queries:
select user where id = 1 and select works where user_id = 1.
So basically in order to be able to execute the second query (fetch relationship data) you need to include id (or whichever column you're referencing) in you select statement.
Fix:
$user = User::select(['uuid','name','about', 'id'])->with(['education','work'])->first();
Same principle in different forms applies to all relationships. For example in the inverse of hasMany which is belongsTo you would need to select the foreign key (for example user_id).
I have the following prices-table:
shop_id (int)
product_id (int)
price (float)
created (DateTime)
Every hour a cronjob checks the shops and inserts new entries (current prices) into these price-table.
Now I want to display the newest price for a product. I have to GROUP BY the shop_id because I only want one price per shop but I only want the newest entry (created).
Can I solve this with Eloquent Query-Builder or do I have to use raw SQL? Is it possible to pass the result of a raw SQL-query into a model if the columns are the same?
You can try it as:
Price::select('*', DB::raw('MAX(created_at) as max_created_at'))
->groupBy('shop_id')
->get()
Assuming model name is Price
Eloquent (purist) approach:
Price::orderBy('created', 'desc')->groupBy('shop_id')
->get('shop_id', 'price');
References:
https://laravel.com/api/5.3/Illuminate/Database/Query/Builder.html#method_orderBy
https://laravel.com/api/5.3/Illuminate/Database/Query/Builder.html#method_groupBy
https://laravel.com/api/5.3/Illuminate/Database/Query/Builder.html#method_get
*untested though
Q: Is it possible to pass the result of a raw SQL-query into a model if the columns are the same?
A: you could pass it to Model's contructor - but it might need model's field to be fillable - or hydrate a model. Alternatively, just access it like an keyed-array, ie. $something[0]['price'] <-- assuming an array of prices with price column.
I solved the problem without QueryBuilder. Instead I use a raw SQL-statement and generating the models with the hydrateRaw()-function of the Model-class.
$prices = Price::hydrateRaw( 'SELECT p.*
FROM prices p
INNER JOIN (
SELECT shop_id, max(created_at) AS max_ca
FROM prices p1
GROUP BY shop_id
) m ON p.shop_id = m.shop_id AND p.created_at = m.max_ca');