cx_Oracle 'SELECT INTO' 绑定变量问题 - ORA-01036：非法变量名称/编号

Question

I am getting an "illegal variable name" error with the code below. One is an out parameter, not sure if this syntax works with out parameters, but have also tried a few variations incluing passing a tuple of values in with:1, :2 syntax - that doesn't work either.

def no_snapshot_for_day(timestamp):
    # Do we have a snaphot already today
    no_snapshot = True
    snapshot_count = cursor_analytics.var(cx_Oracle.NUMBER)

    sql = "SELECT COUNT(1) INTO :v1 FROM PYTHON_SNAPSHOT WHERE SNAPSHOT_DATE=trunc(:v2) AND SNAPSHOT_STATUS='OK'"

    cursor_analytics.execute(sql,{"v1":snapshot_count, "v2":timestamp})


    if snapshot_count.getvalue() > 0:
        no_snapshot = False

    return no_snapshot

Answer 1

'select into' is a PL/SQL SQL syntax. Technically you can execute

sql = "BEGIN SELECT COUNT(1) INTO :v1 FROM PYTHON_SNAPSHOT WHERE SNAPSHOT_DATE=trunc(:v2) AND SNAPSHOT_STATUS='OK'; END;"

but in practice, just do a 'select' and then fetch the data, something like this (untested) code:

with connection.cursor() as cursor_analytics:
    sql = "SELECT COUNT(1) as snapshot_count FROM PYTHON_SNAPSHOT WHERE SNAPSHOT_DATE=trunc(:v2) AND SNAPSHOT_STATUS='OK'"
    cursor_analytics.execute(sql,{"V2": timestamp})
    (snapshot_count,) = cursor_analytics.fetchone()
    print(snapshot_count)