Is it possible to do selection from the database similar to this sql statment with laravel? Or will I have to add a win_percent column and do the calculation manually when adding new entries to the database?
select *, wins / (wins + losses) AS win_percent
Related
Add column in Table items based on left join on item_category table. I want to add column itemcategory_category in the items table based on the left join
=ADDCOLUMNS (
items, LOOKUPVALUE (
'item_category'[ITEMCATEGORY_CATEGORY],
'items'[KEY_PRODUCTCATEGORY], item_category[KEY_PRODUCTCATEGORY]
)
)
Items Table
KEY_PRODUCTCATEGORY
1
item_category table
KEY_PRODUCTCATEGORY ITEMCATEGORY_CATEGORY
1 A
If you have one to one relationship
Table = ADDCOLUMNS(items,"new",RELATED(item_category[ITEMCATEGORY_CATEGORY]))
If you have no relationship
Table 2 = ADDCOLUMNS(items,"new",CALCULATE(MAXX(filter(item_category,item_category[KEY_PRODUCTCATEGORY]=MAX(items[KEY_PRODUCTCATEGORY])),item_category[ITEMCATEGORY_CATEGORY])))
If you are only keen on LOOKUPVALUE with or without relationship. LOOKUPVALUE is not dependent upon any relationship but it has performance issues.
Table 3 = ADDCOLUMNS(items,"new",LOOKUPVALUE(item_category[ITEMCATEGORY_CATEGORY],item_category[KEY_PRODUCTCATEGORY],items[KEY_PRODUCTCATEGORY]))
I tested out with following and it works fine.
I am using Laravel Backpack with Postgres. I am wanting to groupBy (or distinct?) by a column to limit the list view. I have a single table that I want to groupBy thread_id. My latest attempt has been something like this:
$this->crud->groupBy('thread_id');
That code returns the error:
message: "SQLSTATE[42803]: Grouping error: 7 ERROR: column "messages.created_at" must appear in the GROUP BY clause or be used in an aggregate function
(SQL: select count(*) as aggregate from "messages" where "to_user_id" = 2 or "from_user_id" = 2 group by "thread_id" order by "thread_id" desc, "created_at" desc)"
Has anyone ran into this issue, specifically with Backpack?
I have a model User that has many Orders. Orders have many products, with the pivot table order-product. I don't want to preload and iterate through the orders if at all possible.
I need to return users where
signed_date === true on User
order_date on Order is after signed_date on User
order-product shows product hasn't been paid
I am failing on number 2.
In the following code, the first query within whereHas is wrong. I don't know how to reference the signed date of the user from within the where has. If I was iterating through users in a collection I could do something like ($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'm trying to create a database view via a migration in Laravel 5.2 as I need to hand a fairly complex query to a view. I have models / tables for leagues, teams, players, and points. Each one has a hasMany / belongsTo relationship with the one before it. The goal is to create a table where each row is a league name, a sum of all remaining points for the league, and a count of points.remnants where the value of points.remnants > 4.
Major Edit:
What I have so far is
DB::statement( 'CREATE VIEW wones AS
SELECT
leagues.name as name,
sum(points.remnants) as trem,
count(case when points.remnants < 4 then 1 end) as crem
FROM leauges
JOIN teams ON (teams.league_id = leagues.id)
JOIN players ON (players.team_id = teams.id)
JOIN points ON (points.player_id = players.id);
' );
This does not throw any errors, but it only returns one row and the sum is for all points in all leagues.
What I'm looking for is to create a table where there is a row for each league, that has league name, total remaining points for that league, and total points with less than 4 remaining per league.
Marked as solved. See the accepted answer for most of this issues. The one row problem was because I wasn't using GROUP BY with the count().
It looks to me like the problem is your SQL syntax. Here's what you wrote:
CREATE VIEW wones AS SELECT (name from leagues) AS name
join teams where (leagues.id = team.country_id)
join players where (teams.id = players.team_id)
join points where (players.id = points.player_id)
sum(points.remnants) AS trem
count(points.remnants where points.remnants < 4) AS crem
The problem is with the way you've mixed FROM and JOIN clauses with column specifications. Try this:
CREATE VIEW wones AS
SELECT
leagues.name,
sum(points.remnants) AS trem
sum(IF(points.remnants<4, 1, 0)) AS crem
FROM leagues
JOIN teams ON (leagues.id = team.country_id)
JOIN players ON (teams.id = players.team_id)
JOIN points ON (players.id = points.player_id);
I've reformatted it a bit to make it a little clearer. The SQL keywords are capitalized and the various clauses are separated onto their own lines. What we're doing here is specifying the columns, followed by the table specifications - first the leagues table, then the other tables joined to that one.