如果不存在零值，則只會返回SQL記錄

Question

這是我的MySQL數據庫中的註冊表。

SIGNUP 
id (int) 
customer (int) 
helper (int) 
eid (int) 
..plus more fields 

當我想讓它返回數據庫中的記錄時，此查詢返回0結果。情況是，SIGNUP表有一個記錄，客戶= 11，幫助= 0，批准= 0

如果助手字段填充的數字不是0，那麼記錄會返回，但如果它是0，那麼那裏是0條記錄返回。如果我拿出第二條選擇線（包含v.field1，v.field2等），那麼它也可以工作。問題似乎是沒有數據要從幫助列中提取，因此它不允許返回任何其他內容，但仍有其他字段要返回的數據。打開想法和所有幫助表示讚賞！非常感謝。

SELECT 
    u.id cId, u.first cFirst, u.email cEmail, u.username cUsername, 
    v.id hId, v.first hFirst, v.email hEmail, v.username hUsername, 
    s.customer, s.helper, s.eid EID, s.approved, 
    e.name, DATE_FORMAT(e.date, '%W, %b %e %Y %l:%i %p') date, e.summary, e.street, e.city, e.state, e.zip eZip 
FROM signup s 
INNER JOIN events e ON e.id = s.eid 
INNER JOIN users u ON u.id = s.customer 
INNER JOIN users v ON v.id = s.helper 
WHERE 
    (s.customer = 11 OR s.helper = 11) 
AND e.date > sysdate() 
ORDER BY e.date asc 

Answer 1

試試這個：

SELECT 
    u.id cId, u.first cFirst, u.email cEmail, u.username cUsername, 
    v.id hId, v.first hFirst, v.email hEmail, v.username hUsername, 
    s.customer, s.helper, s.eid EID, s.approved, 
    e.name, DATE_FORMAT(e.date, '%W, %b %e %Y %l:%i %p') date, e.summary, e.street, e.city, e.state, e.zip eZip 
FROM signup s 
INNER JOIN events e ON e.id = s.eid 
INNER JOIN users u ON u.id = s.customer 
left JOIN users v ON v.id = s.helper 
WHERE (s.customer = 11 OR s.helper = 11) 
AND e.date > sysdate() 
ORDER BY e.date asc 

Answer 2

如果我理解正確，您需要一個LEFT JOIN。這樣，即使沒有匹配的幫助器，您也可以獲得所有行。

SELECT 
    u.id cId, u.first cFirst, u.email cEmail, u.username cUsername, 
    v.id hId, v.first hFirst, v.email hEmail, v.username hUsername, 
    s.customer, s.helper, s.eid EID, s.approved, 
    e.name, DATE_FORMAT(e.date, '%W, %b %e %Y %l:%i %p') date, e.summary, e.street, e.city, e.state, e.zip eZip 
FROM signup s 
INNER JOIN events e ON e.id = s.eid 
INNER JOIN users u ON u.id = s.customer 
LEFT JOIN users v ON v.id = s.helper 
WHERE 
    (s.customer = 11 OR s.helper = 11) 
AND e.date > sysdate() 
ORDER BY e.date asc