How to combine these multiple queries in laravel eloquent - laravel

Question

I have the following query, where the final result I want is the $rate
// get latest effective date
$effectiveDate = CpfEffectiveDate::where('effective_from', '<=', $currentDate)
->orderBy("effective_from", 'DESC')
->first();
// get scheme related to the effective date and citizenship type
$scheme = CpfScheme::where("cpf_citizenship_id", $request->cpf_citizenship_id)
->where('cpf_effective_date_id', $effectiveDate->id)
->first();
// get rate based on scheme and other data
$rate = CpfRate::where("cpf_scheme_id", $scheme->id)
->where("minimum_wage", '<', ceil($totalWage)) // query does not accept floats. should be acceptable as wage tiers should be integers
->where("minimum_age", '<', $request->employee_age)
->orderBy('minimum_wage', 'DESC')
->orderBy('minimum_age', 'DESC')
->first();
How can I combine all 3 queries into a single one?
First I get the correct effective date from the first table, after which I use it to find the correct scheme (together with a citizenship_id) which I use to find the correct rate.
Here are the following models:
CpfRate
class CpfRate extends Model
{
protected $table = "cpf_rates";
protected $primaryKey = "id";
protected $hidden = ["created_at", "updated_at"];
public function scheme()
{
return $this->belongsTo(CpfScheme::class, "cpf_scheme_id");
}
protected $fillable = [
"minimum_age",
"minimum_wage",
"employer_percentage",
"employee_percentage",
"employee_offset_amount", // used for special cases, such as -500 for percentage = 0.15 * (TW - 500)
"ordinary_wage_cap", // ordinary wage cap
];
}
CpfScheme
class CpfScheme extends Model
{
protected $table = "cpf_schemes";
protected $primaryKey = "id";
protected $hidden = ["created_at", "updated_at"];
public function citizenship()
{
return $this->belongsTo(CpfCitizenship::class, "cpf_citizenship_id");
}
public function effectiveDate()
{
return $this->belongsTo(CpfEffectiveDate::class, "cpf_effective_date_id");
}
}
CpfEffectiveDate
class CpfEffectiveDate extends Model
{
protected $table = "cpf_effective_dates";
protected $primaryKey = "id";
protected $hidden = ["created_at", "updated_at"];
// mutated to dates
protected $dates = ['effective_from'];
public function schemes() {
return $this->hasMany(CpfScheme::class, "cpf_effective_date_id");
}
}
CpfCitizenship
class CpfCitizenship extends Model
{
protected $table = "cpf_citizenships";
protected $primaryKey = "id";
protected $hidden = ["created_at", "updated_at"];
// fields
protected $fillable = ['description'];
public function schemes() {
return $this->hasMany(CpfScheme::class, "cpf_citizenship_id");
}
}

Answer 1

$rate = CpfRate::select('cpf_rates.*')
->where('cpf_scheme_id', '=', function ($query) use ($request) {
$query->select('id')
->from('cpf_schemes')
->where("cpf_citizenship_id", $request->cpf_citizenship_id)
->where('cpf_effective_date_id', '=', function($query, $currentDate) {
$query->select('id')
->from('cpf_effective_dates')
->where('effective_from', '<=', $currentDate)
->orderBy("effective_from", 'DESC')
->limit(1);
})
->first();
})
->where("minimum_wage", '<', ceil($totalWage)) // query does not accept floats. should be acceptable as wage tiers should be integers
->where("minimum_age", '<', $request->employee_age)
->orderBy('minimum_wage', 'DESC')
->orderBy('minimum_age', 'DESC')
->first();
I did not tested but what only here can be problem is $currentdate, so if it is problem just use Carbon class to get current date directly in query.