Python MySQL DB executemany does not work on one value

Question

I am trying to do a batch insert for a single value (row), I am trying to use the executemany function to do so, but it will not work it returns TypeError: not all arguments converted during string formatting. However, when I add an extra value it does work

So... It will return an error here:

entries_list=[("/helloworld"),
                ("/dfadfadsfdas")]
cursor.executemany('''INSERT INTO fb_pages(fb_page)
        VALUES (%s)''', entries_list)

But not here:

entries_list=[("/helloworld", 'test'),
                ("/dfadfadsfdas", 'rers')]
cursor.executemany('''INSERT INTO fb_pages(fb_page, page_name)
        VALUES (%s, %s)''', entries_list)

Korem · Accepted Answer · 2014-06-21T09:06:13.177

Writing ("/helloworld") is the same as writing "/helloworld". To create a tuple you need ("/helloworld", ).

What you're doing is actually running this:

cursor.executemany('''INSERT INTO fb_pages(fb_page)
    VALUES (%s)''', ["/helloworld","/dfadfadsfdas"])

And now the error you're receiving makes perfect sense - you're supplying two arguments with only one place holder. Defining entries_list as follows would solve the problem:

entries_list=[("/helloworld",),
            ("/dfadfadsfdas",)]

score 2 · Answer 2 · answered Nov 19 '19 at 19:05

In addition to making tuple with an additional , at the end as pointed by Karem

entries_list=[
    ("/helloworld",),
    ("/dfadfadsfdas",)
]

You could also just pass in lists and that will sort it out for you just as good when you are using parameterized query.

    entries_list=[
      ["/helloworld"],
      ["/dfadfadsfdas"]
]

Python MySQL DB executemany does not work on one value

2 Answers2