MySQL python 连接器更新错误：检查正确的语法以在 %s 附近使用。 出了什么问题？

Question

this should be relatively quick and easy:

When I run this in my python IDE

mycursor.executemany("UPDATE table42 SET date = %s ", [('2020-05-11')])

For some reason it is getting completely tripped up at the string placeholder (%s). The reason I am using executemany is because soon that string will be replace by a variable using today.strftime('%Y-%m-%d') so I need it to be more flexible.

The error is as follows: mysql.connector.errors.ProgrammingError: 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '%s' at line 1 mysql.connector.errors.ProgrammingError: 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '%s' at line 1

If someone could help me figure out what I'm doing wrong it would be greatly appreciated.

Answer 1

There needs to be a comma after the date string, so that the list is a list of tuples (it's commas that create tuples, not the parentheses).

mycursor.executemany("UPDATE table42 SET date = %s ", [('2020-05-11',)])

This is because the DB API requires that parameters

be provided as sequence or mapping

(Technically a string is a sequence, but here it would be of the wrong length. mysql-connector rejects a string in any case I think, pymysql would accept one in this IIRC. But making the parameters a tuple is definitely the most portable way to code this)