Python选择存在带有变量的SQLite3

Question

I am to be unable to get the following code to work. I know how to use python variables in queries, but somehow I can't get this right. The query works fine when I hard code the 'icaocode' variable in the query, but not if I try to use a variable. What is wrong with this code?

icaocode = input()

c.execute("SELECT EXISTS(SELECT 1 FROM airports WHERE ICAO = ?)", (icaocode))
if c.fetchone():
    print("Found!")
else:
    print("Not found...")

Received error:

sqlite3.ProgrammingError: Incorrect number of bindings supplied. The current statement uses 1, and there are 4 supplied.

Answer 1

In Python, wrapping an expression in parentheses does not make any difference, (icaocode) is exactly the same as icaocode .

The execute method expects some kind of list of parameters, so it sees the string as a sequence of four characters.

To tell Python that you want a tuple with a single element, you have to add a comma:

c.execute("... WHERE ICAO = ?", (icaocode,))