T_STRING错误 - 尝试在SQL where语句中使用PHP数组

I feel like I'm making a rookie error here somewhere but can't figure out what's going wrong. I am using PHP and mySQL. I have an array $users that stores a current user's information. The array is storing the customer id (cid, its an integer). So I'm trying to pull information that is only tagged to a specific customer. My code is:I feel like I'm making a rookie error here some