Question

我正在尝试从当天没有事件的场地表中检索行。

这是我检索事件的方式：

SELECT
    events.*,
    venues.*,
    party_types.PARTYTYPE
FROM events
INNER JOIN venues 
    ON events.VENUE_LOCATION = venues.ID
WHERE start_datetime >= '$DATE_START_SELECTED'
AND end_datetime < '$DATE_END_SELECTED' 
GROUP BY events.ID

$ DATE_START_SELECTED 和 $ DATE_END_SELECTED 是PHP变量，基本上说在Date1和Date2之间执行所有事件。

这就是我目前检索场地的方式：

SELECT
venues.*
FROM venues
GROUP BY venues.VENUE_NAME

如何检索所有场所 当天没有举办任何活动（取决于PHP变量）？

谢谢大家！：）

Answer 1

SELECT
venues.*
FROM venues
LEFT JOIN events ON events.VENUE_LOCATION = venues.ID  AND start_datetime >= '$DATE_START_SELECTED' AND end_datetime < '$DATE_END_SELECTED'
where events.VENUE_LOCATION IS NULL
GROUP BY venues.VENUE_NAME

Answer 2

SELECT
venues.*,
FROM venues 
LEFT JOIN events
ON events.VENUE_LOCATION = venues.ID
WHERE start_datetime >= '$DATE_START_SELECTED'
AND end_datetime < '$DATE_END_SELECTED' 
AND events.VENUE_LOCATION IS NULL

Answer 3

试试这个，我相信它不会表现得很好，但它会给出正确答案。

SELECT
venues.*
FROM venues
WHERE ID NOT IN (SELECT
    VENUE_LOCATION
    FROM events
    WHERE start_datetime >= '$DATE_END_SELECTED'
    OR end_datetime < '$DATE_START_SELECTED')
GROUP BY venues.VENUE_NAME

检索当天没有活动的场地

3 个答案: