我想加入2只選擇一個:如何加入2個SELECT查詢當查詢之一是統一
SELECT user_email FROM users WHERE user_id = ?
,另一個選擇是
SELECT f.friends_friend AS user_id,
users.username AS friend_name,
users.user_avtr AS profile_pic
FROM friends as f
LEFT OUTER JOIN(
SELECT user_id,username,users.user_avtr FROM users
)AS users
ON f.friends_friend = users.user_id
WHERE f.friends_member = ?
UNION
SELECT f.friends_member AS user_id,
users.username AS friend_name,
users.user_avtr AS profile_pic
FROM friends as f
LEFT OUTER JOIN(
SELECT user_id,username,users.user_avtr
FROM users
)AS users
ON f.friends_member = users.user_id
WHERE f.friends_friend = ?
我想運行的2個查詢在一個查詢中
爲什麼你不能只添加users.user_email到第二個查詢中的SELECT語句,因爲你已經加入到users表中了? – 2011-12-31 17:55:37
鑑於你的帖子中有大量的信息,喬納森的問題似乎很合理。他的假設被你對他的回答的評論證明是錯誤的,但是你應該更詳細地闡述你的查詢中發生了什麼,他們是否應該得到與他們的論證相同的價值,以及結果應該是什麼樣子。 – 2011-12-31 23:08:02