How Can I Safely Use Python String Formatting with SQL Wildcards and the LIKE Operator?

Python String Formats with SQL Wildcards and LIKE

When attempting to construct SQL queries that include wildcards and the LIKE operator, complications with Python's string formatting can arise. Several approaches are presented in this article to help resolve these issues.

The first approach, using the string replacement syntax, resulted in a "value error." This error stemmed from Python using '%%s%' to specify two consecutive percent signs, leading to an unexpected format character. Enclosing the wildcard in double backslashes (%) corrects this issue.

The third approach correctly generated the query, but triggered errors from MySQLdb due to insufficient arguments. This was resolved by passing two arguments to the execute() method, the first being the query and the second being the wildcard(s).

Finally, the recommended approach involves using a placeholder for the wildcard. Instead of embedding the wildcard into the string, a "hole" is created in the query where a value can be dynamically substituted. The placeholder is then filled using a tuple containing the wildcard parameters. This method ensures that the query string remains intact and protected from SQL injection vulnerabilities.

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