实现mysql的where的if判断

Question

如何实现mysql的if判断，现在有一个表，表里有两个关键字段
SELECT * FROM house WHERE price='8500' OR shoufu='30'
我是想，当php传入的$price如果为空就sql查找语句就是
SELECT * FROM house WHERE shoufu='30'
当php传入的$shoufu如果为空就sql查找语句就是
SELECT * FROM house WHERE price='8500'
用or判断是不可以的，就想用if判断
另外想问在thinkphp5中是如何在where中实现if else sql语句判断的

Answer 1

$map = [];
if(!empty($price))
{
    $map['price'] = $price;
}
if(!empty($shoufu))
{
    $map['shoufu'] = $shoufu;
}
Db::table('xxxxx')->where($map)->select();