Pandas DataFrame.to_sql() error - not all arguments converted during string formatting

Question

Python Version - 2.7.6

Pandas Version - 0.17.1

MySQLdb Version - 1.2.5

DataFrame.to_sql() is throwing pandas.io.sql.DatabaseError: Execution failed on sql 'SELECT name FROM sqlite_master WHERE type='table' AND name=?;': not all arguments converted during string formatting

Python Code Snippet

con = MySQLdb.connect('localhost', 'root', '', 'product_feed')
cur = con.cursor()
cur.execute("SELECT VERSION()")
connection_result = cur.fetchall()
print connection_result[0][0]     #It prints 5.5.44-0ubuntu0.14.04.1

table_column = ['A', 'B', 'C']
created_data = numpy.array([numpy.arange(10)]*3).T
df = pandas.DataFrame(data=created_data ,columns=table_column)
df.to_sql('test_table', con)

The error comes at the execution of df.to_sql('test_table', con) line.

Error Details

  File "/home/yogi/yogi/mlPython/product_feed/etl_pf/process_data.py", line 298, in render_df
    df.to_sql('test_table', con)
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/pandas/core/generic.py", line 1003, in to_sql
    dtype=dtype)
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/pandas/io/sql.py", line 569, in to_sql
    chunksize=chunksize, dtype=dtype)
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/pandas/io/sql.py", line 1640, in to_sql
    table.create()
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/pandas/io/sql.py", line 685, in create
    if self.exists():
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/pandas/io/sql.py", line 673, in exists
    return self.pd_sql.has_table(self.name, self.schema)
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/pandas/io/sql.py", line 1653, in has_table
    return len(self.execute(query, [name,]).fetchall()) > 0
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/pandas/io/sql.py", line 1554, in execute
    raise_with_traceback(ex)
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/pandas/io/sql.py", line 1543, in execute
    cur.execute(*args)
  File "/home/yogi/yogi/mlenv/local/lib/python2.7/site-packages/MySQLdb/cursors.py", line 187, in execute
    query = query % tuple([db.literal(item) for item in args])
pandas.io.sql.DatabaseError: Execution failed on sql 'SELECT name FROM sqlite_master WHERE type='table' AND name=?;': not all arguments converted during string formatting

I checked that pandas 0.17.1 is mostly using .format() so this error should not arise because of % formatting.

It would be great help if someone could suggest some work around. I do not want to try this with cursor.execute()

Answer 1

Parameters:

con : SQLAlchemy engine or DBAPI2 connection (legacy mode)

Using SQLAlchemy makes it possible to use any DB supported by that library. If a DBAPI2 object, only sqlite3 is supported.

flavor : ‘sqlite’, default None

Deprecated since version 0.19.0: ‘sqlite’ is the only supported option if SQLAlchemy is not used.

It will be fine if you use SQLAlchemy instead of MySQLdb.