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conn = pymysql.connect(host='localhost',user='user',password='password',db='mydb',charset='utf8')
cur = conn.cursor(pymysql.cursors.DictCursor)
try:
    query = 'select * from test where id = 1;abcd'
    cur.execute(query)
    res = cur.fetchone()
    print(res)
except Exception as e:
    print(e)

try:
    query = 'select * from test where id = 2;'
    cur.execute(query)
    res = cur.fetchone()
    print(res)
except Exception as e:
    print(e)

代码的结果如下：

{'name': '', 'score': 1.1, 'id': 1}
(1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'abcd' at line 1")

第一行{'name': '', 'score': 1.1, 'id': 1}来自第一个;中try...except...之前的第一个查询。然后错误消息来自第二个try...except...，但它来自sql查询abcd，这意味着第二个cur.execute(query)中的try...except...产生异常，因为{ {1}}和abcd未执行。

那么如何忽略select * from test where id = 2;并使第二个查询按预期执行？

原始问题
我正在用python构建一个Web服务器。我使用MySQL作为数据库，使用pymysql作为数据库的接口。

现在我遇到了一个问题：
当某个sql查询由于abcd而出错时，即使我使用了;，该程序也会被阻止。这是一个例子：

try...except...

如您所见，由于import pymysql import pymysql.cursors conn = pymysql.connect(host='localhost',user='user',password='password',db='mydb',charset='utf8') cur = conn.cursor(pymysql.cursors.DictCursor) try: query = 'select * from test where id = 1;abcd' <--- exception! cur.execute(query) res = cur.fetchone() print(res) except Exception as e: print(e) query = 'select * from test where id = 2;' cur.execute(query) res = cur.fetchone() print(res)部分，第一个query是非法的。所以它会产生错误。但是，;abcd无法捕获此异常，因为我发现try...except...未执行。以下是我收到的消息：

print(e)

我无法理解为什么{'score': 1.1, 'name': '', 'id': 1} Traceback (most recent call last): File "db_mysql.py", line 23, in <module> cur.execute(query) File "/usr/local/lib/python3.5/site-packages/pymysql/cursors.py", line 161, in execute while self.nextset(): File "/usr/local/lib/python3.5/site-packages/pymysql/cursors.py", line 103, in nextset return self._nextset(False) File "/usr/local/lib/python3.5/site-packages/pymysql/cursors.py", line 98, in _nextset conn.next_result(unbuffered=unbuffered) File "/usr/local/lib/python3.5/site-packages/pymysql/connections.py", line 860, in next_result self._affected_rows = self._read_query_result(unbuffered=unbuffered) File "/usr/local/lib/python3.5/site-packages/pymysql/connections.py", line 1057, in _read_query_result result.read() File "/usr/local/lib/python3.5/site-packages/pymysql/connections.py", line 1340, in read first_packet = self.connection._read_packet() File "/usr/local/lib/python3.5/site-packages/pymysql/connections.py", line 1014, in _read_packet packet.check_error() File "/usr/local/lib/python3.5/site-packages/pymysql/connections.py", line 393, in check_error err.raise_mysql_exception(self._data) File "/usr/local/lib/python3.5/site-packages/pymysql/err.py", line 107, in raise_mysql_exception raise errorclass(errno, errval) pymysql.err.ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'abcd' at line 1")无法捕获错误。此外，似乎产生错误的查询是try...except...，而不是abcd。如果我是对的，我认为select * from test where id = 1;abcd会将此查询分为两个查询。

此外，如果我删除;，这意味着第一个查询变为;，query = 'select * from test where id = 1abcd'可能会捕获错误，因此可以按预期执行第二个查询。 />

所以我的问题是：为什么try...except...无法捕获错误？我该怎么做才能处理所有sql错误，以免程序被阻止？

Answer 1

所以我的问题是：为什么try ... except ...无法捕获错误？什么我该怎么做才能处理所有的SQL错误，这样程序就不会被阻止？

也许具有很好的异常名称？

try:
    …
except pymysql.err.ProgrammingError as except_detail:
        print("pymysql.err.ProgrammingError: «{}»".format(except_detail))

查看在help(pymysql.err)或PyMySQL's Github上键入的所有例外情况

pymysql：一次尝试除了无法捕获多sql错误

1 个答案: