PHP Mysql查询更新多个表，即使某些表为空

Question

      $update = ("UPDATE branch, custodian, atm_machine_list, computer_list 
        SET branch.branch_name = '$branch_name', 
            custodian.branch_name = '$branch_name', 
            atm_machine_list.branch_name = '$branch_name',
            computer_list.branch_name = '$branch_name',
            branch.branch_code = '$branch_code',
            branch.branch_address = '$branch_address',
            branch.manager = '$manager',
            branch.contact = '$contact' 
        WHERE branch.branch_name LIKE '%$edit_id%'
        AND custodian.branch_name LIKE '%$edit_id%'
        AND atm_machine_list.branch_name LIKE  '%$edit_id%'
        AND computer_list.branch_name LIKE '%$edit_id%'");

我正在尝试更新多个表（分支，托管人，atm_machine_list，computer_list）
我希望即使某些表为空，我的查询仍会更新。

例如，保管人有一个branch_name，而atm_machine_list上没有分支名称，那么不管atm_machine_list为何，它仍会更新，但同时会更新保管人。

希望有人会帮助我。 谢谢