交叉引用多個表

Question

什麼，我試圖做的是從多個表中獲取數據，假設我有我的查詢結果如下：

的數字列ticket_item_type代表某個表。例如，2代表tbl_company，3代表tbl_lease。然後細節表示該表中某個記錄的ID。

假設我想使用ticket_item_type和details來獲取這些記錄的標題。是否可以嵌入到結果中？或者我應該爲每個單獨查詢。

我知道JOIN，但我只是單桌嗎？

下面是上面的圖片我的MySQL查詢：

SELECT * 
FROM 
    (SELECT * 
    FROM ticket_items 
    WHERE hs_customer = 1 
    AND ticket IN 
     (SELECT id 
     FROM tickets 
     WHERE hs_customer='1' 
      AND ticket_status = 'dispatch_reviewed') 
    AND ticket IN 
     (SELECT ticket 
     FROM ticket_items 
     WHERE ticket_item_type = 5 
      AND details = '159')) AS TB1 
WHERE ticket_item_type IN (3, 
          2, 
          8) 

Answer 1

你可以嘗試這樣的事：

SELECT 
    TB1.*, 
    CASE 
    WHEN TB1.ticket_item_type = 2 THEN t2.title 
    WHEN TB1.ticket_item_type = 3 THEN t3.title 
    WHEN TB1.ticket_item_type = 8 THEN t8.title 
    ELSE 'NA' 
    END as title 
FROM 
(
    SELECT * 
    FROM ticket_items 
    WHERE hs_customer = 1 
    AND ticket IN (SELECT id FROM tickets WHERE hs_customer='1' AND ticket_status = 'dispatch_reviewed') 
    AND ticket IN (SELECT ticket FROM ticket_items WHERE ticket_item_type = 5 AND details = '159') 
) AS TB1 
LEFT JOIN tbl_company t2 ON TB1.details = t2.id 
LEFT JOIN tbl_lease t3 ON TB1.details = t3.id 
LEFT JOIN tbl_next t8 ON TB1.details = t8.id 
WHERE ticket_item_type IN (3, 2, 8) 

然而，這不是我寧願一個設計。在不查看數據庫的詳細信息的情況下，編寫查詢將很難涵蓋多種類型的ticket_item_type。不過，我希望這個查詢對你有用。