顯示標記

Question

考慮這個SQL查詢：

SELECT * FROM 
( 
SELECT * FROM wp_postmeta 
WHERE 
(
meta_key = 'latitude' AND meta_value *1 BETWEEN 47.3641471102 AND 47.3731524898) 
OR (meta_key = 'longitude' AND meta_value *1 BETWEEN 8.53253429117 AND 8.54583070883) 
) 
AS PostMeta, wp_posts 
WHERE wp_posts.id = PostMeta.post_id order by post_id asc 

它給了我符合特定值或特定值之間的經度之間要麼緯度的所有記錄。我想得到的是符合兩個值的記錄。 但將查詢中的'OR'更改爲'AND'將給我零結果。

我想我需要做某種子查詢，但不知道如何做到這一點。

有人嗎？

Answer 1

你真的只需要從你的經度子查詢中分離你的緯度子查詢。現在，我有更多的時間，我會更明確地返工查詢：

SELECT 
    /* You're only interested in the wp_posts data, right? */ 
    /* You don't care about the data from wp_postmeta. */ 
    /* Only select the data you're actually going to use. */ 
    /* Ideally you'd specify each column in wp_posts that you're */ 
    /* going to use and ignore the rest */ 
    p.* 
FROM 
    wp_posts p 
     JOIN (SELECT post_id FROM wp_postmeta WHERE meta_key = 'latitude' AND CAST(meta_value AS DECIMAL) BETWEEN 47.3641471102 AND 47.3731524898) lat ON p.id = lat.post_id 
     JOIN (SELECT post_id FROM wp_postmeta WHERE meta_key = 'longitude' AND CAST(meta_value AS DECIMAL) BETWEEN 8.53253429117 AND 8.54583070883) long ON p.id = long.post_id 
ORDER BY 
    post_id ASC 

......因爲沒有哪一個wp_postmeta記錄將既是緯度和經度，你不能（至少不近就像這樣）在相同的WHERE子句中匹配它們。相反，創建兩個單獨的調用wp_postmeta表，一個緯度和一個經度，並迫使他們都匹配（因此INNER JOIN，而不是LEFT JOIN）