Python MySQLdb issues (TypeError: %d format: a number is required, not str)

Question

I am trying to do the following insert operation:

cursor.execute("""
                    insert into tree (id,parent_id,level,description,code,start,end)
                    values (%d,%d,%d,%s,%s,%f,%f)
                    """, (1,1,1,'abc','def',1,1)
                    )

The structure of my MYSQL table is:

id int(255),
parent_id int(255),
level int(11),
description varchar(255),
code varchar(255),
start decimal(25,4),
end decimal(25,4)

However when I run my program, I get the error

" File "/usr/lib/pymodules/python2.6/MySQLdb/cursors.py", line 151, in execute query = query % db.literal(args)

TypeError: %d format: a number is required, not str"

Solution 1

The format string is not really a normal Python format string. You must always use %s for all fields.

refer official document:

If args is a list or tuple, %s can be used as a placeholder in the query. If args is a dict, %(name)s can be used as a placeholder in the query.

-> that is: here %s is NOT formatter, but is a placeholder

Solution 2

I got the same error, but it was for a different reason. The problem was that the string included a '%' and that confused Python:

TemplateStr = '[....] % discount rate  [....]  %s and %s
print TemplateStr % ('abc', 'def')

Python interpreted that "% discount" as "%d" and kept complaining because I was feeding it a string ('abc'), not a number.

It took me a long tome to figure it out!

(The solution is to type %% instead of %.)

Comments

[user721975]

Saved me from wasting several more hours !! Thank you very much ! Is there any other way to handle prepared statements? Because this really does not seem be a prepared statement so to speak.

[nosklo]

Use oursql. It can do real parameterization, instead of fake client-side one MySQLdb does.

[user721975]

@nosklo : OK , will give it a try. Thanks.

[SexyBeast]

Darn. I wasted a solid three hours trying to understand why %d is causing error..

[tiankonghewo]

I encountered this problem too. 我刚才也遇到了这个问题,看到回答,我就知道怎么做了

[tiankonghewo]

You must always use %s for all fields. 这句话最实用

[Strabek]

I had to convert decimal values e.g. 1.52456 to string str(value) and then I could use %s. %d did not work even if I converted value to decimal using decimal.Decimal(). Finally I got this working.

[Evan]

Do you have a source for this? I trust you, and this solution worked, but I'd prefer to know an authoritative source and why they chose to mandate this.

[Keith]

@Evan The source code itself. It's just a custom string interpolation implementation. It resembles Python, but isn't the normal Python. This is done to escape the value to prevent SQL injection.