无法在准备好的 INSERT 语句中使用 python mysql.connector 中的 None (NULL) 值

当尝试使用准备好的光标并插入时NULL重视mysql.连接器报错：

mysql.Error: 1210 (HY000): Incorrect arguments to mysqld_stmt_execute

这是准确显示这一点的代码。

from __future__ import print_function
import mysql.connector

def execsql(cursor, sqlstmt):
    try:
        cursor.execute(sqlstmt)
    except mysql.connector.Error as e:
        print("mysql.Error: %s" % e)
    print(cursor._executed, '\n')


def execsqlwithparams(cursor, sqlstmt, params):
    try:
        cursor.execute(sqlstmt, params)
    except mysql.connector.Error as e:
        print("mysql.Error: %s" % e)
    print(cursor._executed, "params:", params, '\n')


def main():
    print("mysql.connector.__version__", mysql.connector.__version__)
    db = mysql.connector.connect(db="test")
    print("mysql.db. get server version", db.get_server_version())
    c1 = db.cursor()
    c2 = db.cursor(prepared=False)
    c3 = db.cursor(prepared=True)

    execsql(c1, "drop table if exists test1")
    execsql(c1, "create table test1 (col1 int not null, col2 int null, primary key(col1))")

    print("insert with pure SQL")
    execsql(c1, "insert into test1(col1,col2) values (1, 1)")
    execsql(c1, "insert into test1(col1,col2) values (2, NULL)")

    print("insert with prepared statement format %s")
    sql = "insert into test1(col1,col2) values (%s, %s)"
    execsql(c2, sql)
    execsqlwithparams(c2, sql, (20, 20))
    execsqlwithparams(c2, sql, (21, None))

    print("insert with prepared statement format %s using prepared cursor")
    sql = "insert into test1(col1,col2) values (%s, %s)"
    execsql(c3, sql)
    execsqlwithparams(c3, sql, (30, 30))
    execsqlwithparams(c3, sql, (31, None))

    execsql(c1, "select * from test1")
    row = c1.fetchone()
    while row:
        print(row)
        row = c1.fetchone()
    db.close()


if __name__ == '__main__':
    status = main()

输出是这样的：

mysql.connector.__version__ 1.2.2
mysql.db. get server version (5, 5, 37)
drop table if exists test1 

create table test1 (col1 int not null, col2 int null, primary key(col1)) 

insert with pure SQL
insert into test1(col1,col2) values (1, 1) 
insert into test1(col1,col2) values (2, NULL) 

insert with prepared statement format %s
mysql.Error: 1064 (42000): 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 '%s, %s)' at line 1
insert into test1(col1,col2) values (%s, %s) 
insert into test1(col1,col2) values (20, 20) params: (20, 20) 
insert into test1(col1,col2) values (21, NULL) params: (21, None) 

insert with prepared statement format %s using prepared cursor
insert into test1(col1,col2) values (%s, %s) 
insert into test1(col1,col2) values (%s, %s) params: (30, 30) 

mysql.Error: 1210 (HY000): Incorrect arguments to mysqld_stmt_execute
insert into test1(col1,col2) values (%s, %s) params: (31, None)

select * from test1 

(1, 1)
(2, None)
(20, 20)
(21, None)
(30, 30)

意想不到的结果是这样的：

mysql.Error: 1210 (HY000): Incorrect arguments to mysqld_stmt_execute
insert into test1(col1,col2) values (%s, %s) params: (31, None)

数据库中缺少行（31，无）。

与最后一种情况中传递的 None 相关的问题可能是由于 None 没有被解释为表中定义的类型所致。