MySQL的子查詢的WHERE IN，但也從IN子

Question

這是在那一刻滑落我的腦海裏獲得額外的列，讓我們說，我有這樣的代碼：

SELECT * FROM Table1 
    WHERE (FoundCity, FoundState) IN 
    (SELECT city, state, distance 
     FROM Table2 
    ) ; 

我怎麼也弄它拉的距離上面的'主'查詢列？

Answer 1

將子查詢更改爲聯接。然後您可以從任一表中選擇任何列。

SELECT *, t2.distance 
FROM Table1 t1 
INNER JOIN Table2 t2 
ON t1.FoundCity = t2.city AND t1.FoundState = t2.state 

編輯

如果你想保持元組連接語法，你也可以這樣做：

SELECT t1.*, t2.distance 
    FROM t1 INNER JOIN t2 
    ON (t1.FoundCity, t1.FoundState) = (t2.city, t2.state); 

SqlFiddle

Answer 2

SELECT * FROM Table1 as T1 
LEFT JOIN Table2 as T2 on T1.FoundCity = T2.FoundCity AND T1.FoundState = T2.FoundState 

更好的主意是使用左連接。在*中，您可以包含使用T1作爲表1的列的前綴和表2的列的前綴名稱。（例如：T2.state）