mysql - 锁定 MySQL 表在 Tornado 中不起作用

Question

我有这个代码：

# Retreive the users that can obtain permission on the network except the admin
self.lock_tables("read", ['nets_permissions as n', 'users as u'])
usrs = self.db.query("SELECT distinct u.id FROM users as u \
        left outer join nets_permissions as n on u.id = n.user_id \
        where u.id not in \
        (select users.id from users left outer join nets_permissions \
        on users.id = nets_permissions.user_id \
        where nets_permissions.network_id=%s and nets_permissions.perm=3)", netid)
self.unlock_tables()

但我在 Tornado 屏幕中收到此错误：

文件“./wsn.py”，第 571 行，在获取 nets_permissions.network_id=%s 和 nets_permissions.perm=3)"，netid) 引发错误类，错误值 OperationalError：（1100，“表 'users' 未锁定锁定表")

错误在哪里？

Answer 1

解决方案是：

# Retreive the users that can obtain permission on the network except the admin
    self.lock_tables("read", ['nets_permissions as n', 'users as u', 'nets_permissions as m', 'users as v'])
    usrs = self.db.query("SELECT distinct u.id FROM users as u \
                          left outer join nets_permissions as n on u.id = n.user_id \
                          where u.id not in \
                          (select v.id from users as v left outer join nets_permissions as m \
                          on v.id = m.user_id \
                          where m.network_id=%s and m.perm=3)", netid)
    self.unlock_tables()