how to add conditional where clause in sql - mysql

Question

Looking for improved answer
In Laravel, I am using a raw query. My question is how to add where clause depending on variable value
i.e. if $cid is present then the query should be
select * from user where aid=2 and cid=1;
If it is not present
select * from user where aid=2;
Ideally, I can do it like this
if($cid) {
$query = DB::select("select * from user where aid=2 and cid=1");
} else {
$query = DB::select("select * from user where aid=2");
}
Is there any way to do this without the above method?

Answer 1

This can be achieved with conditional clauses.
$users = DB::table('users')
->where('aid', 2)
->when($cid, function ($query) {
$query->where('cid', 1);
})
->get();

Answer 2

Please contextualize your question well, we don't know what kind of condition you are talking about, nor in what sense your question is asked.
normally the comment above would be enough but it is necessary to specify
Here are some examples from the documentation
$users = DB::table('users')
->where('votes', '=', 100)
->where('age', '>', 35)
->get();
$users = DB::table('users')->where('votes', 100)->get();
You may also pass an array of conditions to the where function. Each element of the array should be an array containing the three arguments typically passed to the where method:
$users = DB::table('users')->where([
['status', '=', '1'],
['subscribed', '<>', '1'],
])->get();
I encourage you to read the documentation which is very clear on this subject and to come back to me in case of misunderstanding
here