我建议在其他表的单独行中使用存储值，以便查询。
尽管你是靠 find_in_set 与 whereRaw ```
DB::table('products')
->whereRaw("FIND_IN_SET('L',sizes)")
->paginate(1);

如果你想取准确的尺寸，那么你可以试试

return DB::table('products')->where(['sizes',  $size])->paginate(1);

使用 = 而不是 Like .
对于更多的用例，这里有不同的例子。

WHERE sizes LIKE 'L%'   //Finds any values that starts with "L"
WHERE sizes LIKE '%L'   //Finds any values that ends with "L"
WHERE sizes LIKE '%or%' //Finds any values that have "or" in any position
WHERE sizes LIKE '_r%'  //Finds any values that have "r" in the second position
WHERE sizes LIKE 'a_%_%'    //Finds any values that starts with "a" and are at least 3 characters in length
WHERE sizes LIKE 'a%o'  //Finds any values that starts with "a" and ends with "o"

您的代码中也有一个拼写错误
改变这个

return DB::table('products')->where([['sizes', 'LIKE', "%".$size."%"]])->paginate(1);

为了这个

return DB::table('products')->where('sizes', 'LIKE', "%".$size."%")->paginate(1);

希望这有帮助。