結合兩個select查詢

Question

當我使用兩個查詢時，一個被初始調用，第二個在第一個結果循環中被調用。我想結合這兩個查詢，但迄今爲止還沒有辦法。查詢從拉的表是：

+--------------+ +--------------+ +--------------------------+ 
| table_1 | | table_2 | |   table_3   | 
+----+---------+ +----+---------+ +----+----------+----------+ 
| id | name | | id | name | | id | tbl1_id | tbl2_id | 
+----+---------+ +----+---------+ +----+----------+----------+ 
| 1 | tbl1_1 | | 1 | tbl2_1 | | id |  1 |  1 | 
| 2 | tbl1_2 | | 2 | tbl2_2 | | id |  3 |  2 | 
| 3 | tbl1_3 | | 3 | tbl2_3 | | id |  3 |  3 | 
| 4 | tbl1_4 | +----+---------+ +----+----------+----------+ 
+----+---------+ 

有一個許多人table_1和table_3table_2之間一對多的關係。到目前爲止，我一直在使用分隔查詢。一個查詢返回table_1的所有內容，第二個查詢返回連接到table_1到table_3的值table_2。但是，我想廢除循環並減少發送到服務器的查詢數量。我一直在使用一個JOIN嘗試：

SELECT table_1.id, table_1.name, table_2.id, table_2.name 
FROM table_3 
LEFT JOIN table_1 ON (table_3.tbl1_id = table_1.id) 
LEFT JOIN table_1 ON (table_2.tbl2_id = table_2.id) 

這回非常希望，我想，除了它只有返回均table_3從table_1留下了一些值的值。我試過使用子查詢：

SELECT table_1.id, 
    table_1.name, 
    (SELECT table_2.id FROM table_2, table_3 WHERE table_2.id = table_3.tbl2_id AND table_1.id = table_3.tbl1_id) AS tbl_2_id, 
    (SELECT table_2.name FROM table_2, table_3 WHERE table_2.id = table_3.tbl2_id AND table_1.id = table_3.tbl1_id) AS tbl_2_name 
FROM table_1 

這給了ERROR 1242。到目前爲止，我還沒有能夠得到任何工作。我正在尋找的結果與此類似。

+---------------+---------------+---------------+---------------+ 
|table_1.id |table_1.name |table_2.id |table_2.name | 
+---------------+---------------+---------------+---------------+ 
|  1 | tbl1_1 |  1 | tbl2_1 | 
|  2 | tbl1_2 |  |  | 
|  3 | tbl1_3 |  2 | tbl2_2 | 
|  3 | tbl1_3 |  3 | tbl2_3 | 
|  4 | tbl1_4 |  |  | 
+---------------+---------------+---------------+---------------+ 

另外，我想可以訂購兩個table_1.name和table_2.name結果。如果有人有一個建議，請讓我知道。

Answer 1

將LEFT JOIN更改爲RIGHT JOIN，並且兩個連接在查詢中出現的順序解決了此問題。這是工作代碼的副本;

SELECT table_1.id, 
    table_1.name, 
    table_2.id, 
    table_2.name 
FROM table_3 
RIGHT JOIN table_2 ON (table_3.tbl2_id = table_2.id) 
RIGHT JOIN table_1 ON (table_3.tbl1_id = table_1.id) 
ORDER BY table_1.name ASC, table_2.name ASC; 

Answer 2

所以你只是試圖打印出所有的相關配對？如何：

SELECT table_1.id, table_1.name, table_2.id, table_2.name 
FROM table_3 
INNER JOIN table_1 ON table_1.id = table_3.tbl1_id 
INNER JOIN table_2 ON table_2.id = table_3.tbl2_id 
ORDER BY table_1.id, table_2.id 

Answer 3

要想從TABLE_1有沒有匹配的其它表，你應該使用一個外行JOIN而不是INNER JOIN的：

SELECT 
    table_1.id, 
    table_1.name, 
    table_2.id, 
    table_2.name 
FROM table_1 
LEFT JOIN table_3 ON table_3.tbl1_id = table_1.id 
LEFT JOIN table_2 ON table_3.tbl2_id = table_2.id 

結果：

 
table_1.id table_1.name table_2.id table_2.name 
1   'tbl1_1'  1   'tbl2_1'  
2   'tbl1_2'     ''   
3   'tbl1_3'  2   'tbl2_2'  
3   'tbl1_3'  3   'tbl2_3'  
4   'tbl1_4'     ''