ThinkPHP Association preload with

Pre query loading function of associated query , Mainly solved N+1 The problem of this query , Improve performance .

$list = User::select([1,2,3]);
foreach($list as $user){
    
    //  Get the information associated with the user profile model data 
    dump($user->profile);
}

The above code will execute 4 Queries

Use associative preloading

$list = User::with(['profile'])->select([1,2,3]);
foreach($list as $user){
    
    //  Get the information associated with the user profile model data 
    dump($user->profile);
}

If you use the associated pre query function , It can become 2 Queries （ For one-to-one relationships , If you use withJoin Only one query ）, Improve performance .

$list = User::with(['profile'])->select([1,2,3]);
foreach($list as $user){
    
    //  Get the information associated with the user profile model data 
    dump($user->profile);
}

Mainly because with Query changed to in Conditions of the query , Found out at one time 3 strip profile model data
perform sql as follows