How to select common date from three tables in laravel? - eloquent

Question

I have these three tables in my database and I want to select the common date from three tables to calculate the profit of every day , profit of every month, and profit of every year
this is my tables :
Schema::create('expenses', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->float('amount');
$table->string('month');
$table->string('year');
$table->string('date');
});
Schema::create('service_orders', function (Blueprint $table) {
$table->bigIncrements('id');
$table->bigInteger('client_id')->unsigned();
$table->double('total_price', 8, 2)->nullable();
$table->string('month');
$table->string('year');
$table->date('date');
$table
->foreign('client_id')
->references('id')
->on('clients')
->onDelete('cascade');
});
Schema::create('orders', function (Blueprint $table) {
$table->bigIncrements('id');
$table->bigInteger('client_id')->unsigned();
$table->double('total_price', 8, 2)->nullable();
$table->string('month');
$table->string('year');
$table->date('date');
$table
->foreign('client_id')
->references('id')
->on('clients')
->onDelete('cascade');
});

Answer 1

I think your problem can be solved by UNIONS
UNION used to combine the result of two or more tables
SELECT date FROM expenses
UNION ALL
SELECT date FROM service_orders
UNION ALL
SELECT date FROM orders
To use it in Laravel you can check documentation below:
https://laravel.com/docs/5.8/queries#unions