Question

我有以下Python代码：

statement = statement + " OR (TIMESTAMPDIFF(MINUTE, (str_to_date( (SELECT tijd FROM Metingen WHERE SensorID='" + sensor_id + "' ORDER BY MetingID DESC LIMIT 1), '%%d-%%m-%%Y %%H:%%i' )), NOW()) >= " + waarde + " AND MetingID=(SELECT metingID FROM Metingen WHERE SensorID='" + sensor_id + "' ORDER BY metingID DESC LIMIT 1)"

我正在尝试使用str_to_date MySQL函数，但是因此我需要在MySQL查询中使用百分号，这是在Python中生成的。我知道使用%%应该可以解决这个问题，但是当我这样做时，两个百分号都会打印到查询中，查询将无效。

Answer 1

当我在代码中使用硬编码的SQL查询时，我喜欢将它们放在多行字符串中。（参见字符串上的documentation）

QUERY = """
{prefix} 
OR (
    TIMESTAMPDIFF(MINUTE, 
    (str_to_date((
        SELECT tijd 
        FROM Metingen 
        WHERE SensorID='{sensor_id}' 
        ORDER BY MetingID DESC LIMIT 1), 
    '%d-%m-%Y %H:%i' )), 
    NOW()) >= {waarde} 
AND 
    MetingID=(
        SELECT metingID 
        FROM Metingen 
        WHERE SensorID='{sensor_id}' 
        ORDER BY metingID DESC LIMIT 1)
""".strip()

statement = QUERY.format(
    prefix=statement,
    sensor_id=sensor_id,
    waarde=waarde)

没有%%的Python字符串中的百分号（％）

1 个答案: