When trying to use a prepared cursor and insert NULL values, mysql.connector reports an error:
mysql.Error: 1210 (HY000): Incorrect arguments to mysqld_stmt_execute
Here is the code that shows this for sure.
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()
The output is as follows:
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)
Unexpected result:
mysql.Error: 1210 (HY000): Incorrect arguments to mysqld_stmt_execute insert into test1(col1,col2) values (%s, %s) params: (31, None)
And the missing row (31, None) from the database.