然後在內部連接條件下

Question

SELECT col1,col2 FROM t1 INNER JOIN t2 ON t1.col1 = t2.id where t2.col2 ='1' 
SELECT col1,col2 FROM t1 INNER JOIN t2 ON t1.col2 = t2.id where t2.col1 ='1' 

我可以在單個查詢中合併兩個查詢嗎？ 我試過當時使用！

Answer 1

怎麼樣UNION

SELECT col1,col2 FROM t1 INNER JOIN t2 ON t1.col1 = t2.id where t2.col2 ='1' 
UNION 
SELECT col1,col2 FROM t1 INNER JOIN t2 ON t1.col2 = t2.id where t2.col1 ='1' 

Answer 2

SELECT col1,col2 FROM t1, t2 
WHERE 
(t1.col1 = t2.id AND t2.col2 = '1') 
OR 
(t1.col2 = t2.id AND t2.col1 = '1') 

是另一種方式。但UNION也應該真的有效。

Answer 3

這聽起來像你希望兩個選擇之間

SELECT col1, col2 
FROM (
SELECT col1,col2 FROM t1 INNER JOIN t2 ON t1.col1 = t2.id where t2.col2 ='1' 
UNION 
SELECT col1,col2 FROM t1 INNER JOIN t2 ON t1.col2 = t2.id where t2.col1 ='1' 
    ) 
ORDER BY whatever