python 2.7 to python 3.4 error unsupported operand type(s) for %: 'bytes' and 'dict'

问题

I got the following code from How do I get a raw, compiled SQL query from a SQLAlchemy expression? and it worked fine until we moved from Python 2.7 to Python 3.4. I've made a few changes though I'm stuck on

return (comp.string.encode(enc) % params).decode(enc)

with the error unsupported operand type(s) for %: 'bytes' and 'dict'

def compile_query(query):
    dialect = query.session.bind.dialect
    statement = query.statement
    comp = compiler.SQLCompiler(dialect, statement)
    comp.compile()
    enc = dialect.encoding
    params = {}
    for k,v in comp.params.iteritems():
        if isinstance(v, unicode):
            v = v.encode(enc)
        params[k] = sqlescape(v)
    return (comp.string.encode(enc) % params).decode(enc)

回答1:

Thanks to the comments, I ported it to python 3

def compile_query(query):
    dialect = query.session.bind.dialect
    statement = query.statement
    comp = compiler.SQLCompiler(dialect, statement)
    comp.compile()
    enc = dialect.encoding
    params = {}
    for k,v in comp.params.items():
        if isinstance(v, str):
            v = v.encode(enc)
        params[k] = sqlescape(v)
    return (comp.string % params)

来源：https://stackoverflow.com/questions/28227190/python-2-7-to-python-3-4-error-unsupported-operand-types-for-bytes-and-d