使用多個表格進行查詢

Question

SELECT keyword 
FROM 
(
    SELECT tutor_Name AS keyword FROM t 
    UNION 
    SELECT subject_name AS keyword FROM s 
    UNION 
    SELECT institute_name AS keyword FROM i 
) s 
WHERE keyword LIKE '%$queryString%' 
LIMIT 10 

此查詢根據關鍵字顯示帶有主題，導師名稱和城市的列表。現在我需要用更多的值修改這個查詢。例如，列表中有一個導師姓名，我想顯示他/她的當前城市，他/她的個人資料圖片等。所以我需要從我的城市表，地址表，tutorImages表中獲取這些值。所以任何人都可以幫我做這個查詢？

Answer 1

試試這個它會工作：

$q = "SELECT keyword, col, city_name, image_name, tutor_code 
      FROM (
       SELECT tutor_name AS keyword, 'Tutors' AS col, IFNULL(c1.city_name, '') city_name, IFNULL(ti.image_name, '') image_name, tutor_code FROM tutors AS t 
       LEFT JOIN address a ON t.address_id = a.address_id 
       LEFT JOIN city c1 ON a.city_id = c1.city_id 
       LEFT JOIN tutor_images ti ON t.tutor_id = ti.tutor_id and ti.image_type = 'profile' 
       UNION 
       SELECT subjects AS keyword, 'Subject' AS col, '' city_name, '' image_name, '' tutor_code FROM subject 
       UNION 
       SELECT city_name AS keyword, 'City' AS col, '' city_name, '' image_name, '' tutor_code FROM city 
       UNION 
       SELECT institute_name AS keyword, 'Institute' AS col, '' city_name, '' image_name, '' tutor_code FROM institutes 
      ) s 
      WHERE keyword LIKE '%$queryString%' 
      LIMIT 10"; 

Answer 2

嘗試加入。

SELECT table1.field, table2.field, table3.field 
FROM table1 
JOIN table2 ON table1columnToMatch = table2columnToMatch 
JOIN table3 ON table2columnToMatch = table3columnToMatch 
WHERE tableWithKeyword.keyword = $keyword 

Answer 3

與第一個查詢的問題是，你取每個表未經過濾的，他們的工會，他們分明，然後過濾結果的所有結果。這在查詢時間和資源方面相當無效。

這裏您需要的是JOIN。 要了解如何加入工作，閱讀本

http://www.codinghorror.com/blog/2007/10/a-visual-explanation-of-sql-joins.html

這

http://dev.mysql.com/doc/refman/5.5/en/join.html

爲了讓您的查詢應該如何看起來像一個想法：舊的重構

SELECT 

給我一點，從手機切換到電腦..閱讀文章while;）

對不起，花了點時間。我看你已經找到了解決方案。同時，所以我不會打擾挖掘到這不再

Answer 4

試試這個：

SELECT keyword, city_name, image_name 
FROM (
SELECT tname AS keyword, IFNULL(c1.city_name, '') city_name, IFNULL(ti.image_name, '') image_name FROM t 
LEFT JOIN address a ON t.address_id = a.address_id 
LEFT JOIN city c1 ON a.city_id = c1.city_id 
LEFT JOIN tutorImages ti ON t.tutor_id = t1.tutor_id 
UNION 
SELECT sname AS keyword, '' city_name, '' image_name FROM sub 
UNION 
SELECT cname AS keyword, '' city_name, '' image_name FROM c 
UNION 
SELECT iname AS keyword, '' city_name, '' image_name FROM i) s 
WHERE keyword LIKE '%$queryString%' 
LIMIT 10