Python SQLite parameter substitution with wildcards in LIKE

Question

I am attempting to use a parametrized LIKE query with Python's Sqlite library as below:

self.cursor.execute("select string from stringtable where string like '%?%' and type = ?", (searchstr,type)) 

but the ? inside of the wildcard is not being evaluated leaving me with this error:

"sqlite3.ProgrammingError: Incorrect number of bindings supplied. The current statement uses 1, and there are 2 supplied." 

I also tried to use the tagged version of querying with:

like '%:searchstr%' and in the list having {"searchstr":searchstr...

but when I do that the query runs but never returns any results even though manually putting in "like '%a%'"... return hundreds of results as it should

any suggestions please?

Answer 1

The quotes protect either ? or :name from being taken as a place-holder -- they're taken literally. You need to place the percent signs around the string you're passing, and use the plain placeholder without quotes. I.e.:

self.cursor.execute(   "select string from stringtable where string like ? and type = ?",   ('%'+searchstr+'%', type)) 

Note that neither ? is in quotes -- and that's exactly as it should be for them to be taken as placeholders.