Python和MySQLdb:替换表会导致语法错误 [英] Python and MySQLdb: substitution of table resulting in syntax error

问题描述

我需要不时动态地更改表和变量，所以我编写了这样的python方法:

I need to dynamically change tables and variables from time to time, so I wrote a python method like this:

    selectQ ="""SELECT * FROM  %s WHERE %s = %s;""" 
    self.db.execute(selectQ,(self.table,self.columnSpecName,idKey,))
    return self.db.store_result()

但是，这将导致语法错误异常.我尝试对其进行调试，因此我在方法中打印了变量，然后手动将其填充，并且可以正常工作.所以我不确定我在做什么错了吗?

However this results in a syntax error exception. I tried debugging it so I printed the variables in the method and filled them in manually, and that worked. So I am not sure what I am doing wrong ?

是因为我尝试使用表的替代品吗?

Is it because I try to use a substitute for a table ?

我也该如何调试mysqldb以便将替换查询打印为字符串?

Also how do I debug mysqldb so it prints the substituted query as a string ?

推荐答案

DB API中的参数替换仅适用于值-不适用于表或字段.您将需要使用普通的字符串替换:

Parameter substitution in the DB API is only for values - not tables or fields. You'll need to use normal string substitution for those:

selectQ ="""SELECT * FROM  %s WHERE %s = %%s;""" % (self.table,self.columnSpecName)
self.db.execute(selectQ,(idKey,))
return self.db.store_result()

请注意，值占位符有一个双精度%-这样就可以在初始字符串替换中将其保留.

Note that the value placeholder has a double % - this is so that it's left alone by the initial string substitution.

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