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POPython, MySQLdb and escaping table names?
 

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    <p>I may be missing something obvious, but I can't figure out how my code is different from various examples I see in the online documentation for MySQLdb.</p> <p>I'm fairly new to programming python, more experienced with perl. What I'm trying to do is get into certain good habits early on (like in perl I always start with 'use strict; use warnings'), so I'm trying to ensure I create re-usable functions in an independent file (funct.py) to save me time later on down the line.</p> <p>I've got this function for selecting random rows from a table:</p> <pre><code>def returnRandom(conn,countcol,table,field): cursor = conn.cursor() cursor.execute('SELECT MAX(%s) FROM %s',(countcol,table)) maxRow = cursor.fetchone()[0] cursor.execute("SELECT MIN(%s) FROM %s",(countcol,table)) minRow = cursor.fetchone()[0] randomId = random.randrange(minRow,maxRow+1,1) cursor.execute("SELECT ? FROM ? WHERE id &gt;=? LIMIT 1",field,table,randomId) return cursor.fetchone()[0] </code></pre> <p>It's being called like this:</p> <pre><code>msg = funct.returnRandom(conn,"id","testtable","data") </code></pre> <p>Unfortunately it errors out with: _mysql_exceptions.ProgrammingError: (1064, "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 ''testtable'' at line 1")</p> <p>If I put testtable in in place of the %s on the execute line, The query will run but it looks like it runs</p> <pre><code>SELECT MAX('id') FROM testtable; </code></pre> <p>which of course returns 'id'.</p> <p>Given both of those it looks like it's quoting the %s entries when it tries to execute them. I was wondering if anyone could explain how I get it to stop doing that, or how I should actually being doing what I'm trying to achieve? I want the function to be as generic as possible, so relying on data being passed to it by when it's called.</p> <p>edit: I should add, if I substitute in ? marks:</p> <pre><code>.... cursor.execute('SELECT MAX(?) FROM ?',(countcol,table)) File "/usr/lib/pymodules/python2.7/MySQLdb/cursors.py", line 151, in execute query = query % db.literal(args) TypeError: not all arguments converted during string formatting </code></pre>
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