mysql查詢使用另一個查詢的數組結果

Question

我有一個簡單的查詢，查找在給定緯度和經度的特定距離內的城市。

$query = "SELECT city,state,((ACOS(SIN($lat * PI() / 180) * SIN(lat * PI() / 180) + COS($lat * PI() / 180) * COS(lat * PI() / 180) * COS(($lon - lon) * PI() / 180)) * 180 / PI()) * 60 * 1.1515) AS distance FROM us_cities WHERE population<>'' HAVING distance<=30 ORDER BY distance ASC limit 1, 10";

然后顯示結果：

$rows = mysqli_num_rows($result);           
for ($i = 0; $i < $rows; ++$i) {            
$row = mysqli_fetch_assoc($result);
echo $i+1;
echo $row['city'] . "<br />";
echo $row['state'] . "<br />";
}

我想要做的不是回顯結果，取出該數組並執行另一個查詢，該查詢包含另一個表中有關這些城市的信息，然后回顯結果。 有沒有辦法可以做到這一點，而不必做10個子查詢：

Select * FROM table2 WHERE city=city AND state=state;

我如何說“從table1中獲取城市和狀態數組，並使用該數組從table2中選擇所有內容？

Answer 1

兩者之間的簡單INNER JOIN將完成這項工作：

SELECT 
  /* Need to add table name or alias in select list since both tables have these cols */
  us_cities.city,
  us_cities.state,
  ((ACOS(SIN($lat * PI() / 180) * SIN(lat * PI() / 180) + COS($lat * PI() / 180) * COS(lat * PI() / 180) * COS(($lon - lon) * PI() / 180)) * 180 / PI()) * 60 * 1.1515) AS distance 
FROM
   us_cities
   /* Join on city and state */
   INNER JOIN table2 
      ON us_cities.city = table2.cities 
      AND us_cities.state = table2.state
WHERE population <>''
HAVING distance<=30
ORDER BY distance ASC 
limit 1, 10