尝试以下方法:

c.execute("SELECT EXISTS(SELECT 1 FROM airports WHERE ICAO='EHAM')")

if c.fetchone():
    print("Found!")

else:
    print("Not found...")

cursor.execute的返回值是游标(或更精确地引用其自身)，并且独立于查询结果.您可以轻松地检查以下内容:

Return value of cursor.execute is cursor (or to be more precise reference to itself) and is independent of query results. You can easily check that:

 >>> r = c.execute("SELECT EXISTS(SELECT 1 FROM airports WHERE ICAO='EHAM')")
 >>> r is True
 False
 >>> r is False
 False
 >>> r is None
 False

 >>> r is c
 True

另一方面，如果您调用cursor.fetchone结果元组，或者如果没有行通过查询条件，则为None.因此，在您的情况下，if c.fetchone():表示以下之一:

From the other hand if you call cursor.fetchone result tuple or None if there is no row that passes query conditions. So in your case if c.fetchone(): would mean one of the below:

if (1, ):
    ...

或

if None:
    ...