我正在使用php。如何在我的mysql查詢中使用函數？
我想找出與地理緯度和經度給定距離的地方。
我有在MySQL數據庫中一個表叫地方，其中有三列placeId，latitude和longitude。
用戶提供latitude，longitude的地方和distance，然後通過使用下面的公式：
d = 2 * ASIN（SQRT（（SIN（（LAT1-LAT2）/ 2））^ （lat1）cos（lat2）（sin（（lon1-lon2）/ 2））^ 2））;
我可以檢查這些地方是否與用戶給出的距離一致。
我想知道如何編寫查詢和函數來實現此功能。
我在下面的功能創造了MYSQL
DELIMITER $$
DROP FUNCTION IF EXISTS `great_circle_distance`$$
CREATE DEFINER=`root`@`localhost` FUNCTION `great_circle_distance`(
lat1 DOUBLE(10,6),
lon1 DOUBLE(10,6),
lat2 DOUBLE(10,6),
lon2 DOUBLE(10,6)
) RETURNS double(10,2)
DETERMINISTIC
BEGIN
DECLARE delta_lat DOUBLE(10,6);
DECLARE delta_lon DOUBLE(10,6);
DECLARE temp1 DOUBLE(10,6);
DECLARE EARTH_RADIUS DOUBLE(10,2);
DECLARE distance DOUBLE(10,2);
SET lat1 = RADIANS(lat1);
SET lon1 = RADIANS(lon1);
SET lat2 = RADIANS(lat2);
SET lon2 = RADIANS(lon2);
SET delta_lat = lat2 - lat1;
SET delta_lon = lon2 - lon1;
SET temp1 = pow(sin(delta_lat/2.0),2) + cos(lat1) * cos(lat2) * pow(sin(delta_lon/2.0),2);
SET EARTH_RADIUS = 3956.0;
SET distance = EARTH_RADIUS * 2 * atan2(sqrt(temp1),sqrt(1-temp1));
RETURN distance;
END$$
DELIMITER ;
使用它作爲
Select great_circle_distance(z.lat,z.log, 32.2342,-72.42342) AS Distance from tbl_abc AS z;
感謝pinaldesai ...您的回答非常有幫助。非常感謝你... –
歡迎哥們:) – pinaldesai
我創建了一個簡單的PHP函數使用MySQL查詢。
任何查詢都可以在1個簡單函數中執行。
在選擇查詢的情況下，我們可以獲取選定的參數，因爲變量名包含所選的參數值。
對於前：
someuser
someemail
：
<?php
q("select user_name,email_id from users where user_id=48");
echo $user_name; echo "<br>";
echo $email_id;
?>
或你可以通過把 「爲」
<?php
q("select user_name as uname, email_id as email from users where user_id=48");
echo $uname; echo "<br>";
echo $email;
?>
結果輸出會設置自己的變量名如果行數更多的話當選，變量名稱將作爲數組 爲前創建：
<?php
q("select user_name,user_id from users");
for($n=0;$n<count($user_name);$n++)
{
if(count($user_name)==1) // if single row is selected
{
$username_val=$user_name;
$user_ids=$user_id;
}else{
$username_val=$user_name[$n]; // for multiple rows selected
$user_ids=$user_id[$n];
}
echo $username;
}
?>
或你可以通過把「爲」
<?php
q("select user_name as un,user_id as uid from users");
for($n=0;$n<count($user_name);$n++)
{
if(count($user_name)==1) // if single row is selected
{
$username_val=$un;
$user_ids=$uid;
}else{
$username_val=$un[$n]; // for multiple rows selected
$user_ids=$uid[$n];
}
echo $username_val; echo " ";
echo $user_ids; echo "<br>";
}
?>
結果輸出會設置自己的變量名： （如果用戶表具有三排）
User1 4043
User2 4048
User3 4056
創建MySQL連接文件例如：mysql_connect_file。PHP
<?php
$dbc=new mysqli('localhost', 'my_user', 'my_password', 'my_db');
?>
PHP函數低於
<?php
require_once './mysql_connect_file.php';
function q($q)
{
$main_q=$q;
$q= strtolower($q);
global $dbc;
$temp=$q;
$temp=str_replace(" ", "", $temp);
$temp= strtolower($temp);
$temp=".$temp";
if(strpos($temp, "update")==1 || strpos($temp, "insert")==1 || strpos($temp, "delete")==1 || strpos($temp, "alter")==1 || strpos($temp, "create")==1)
{
$rd2= mysqli_query($dbc,$main_q);
if($rd2)
{
return TRUE;
}
else{
$mysql_err= mysqli_error($dbc);
$err= debug_backtrace();
$err_line=$err[0]['line'];
$err_file=$err[0]['file'];
echo "<font color='black'>Error at <b>$err_file on line $err_line </b>query --></font><font color='maroon'>$main_q</font> (<font color='red'> $mysql_err </font>)";
return FALSE;
}
}elseif(strpos($temp, "select")==1){
$qn= str_replace("select ", "", $q);
$qn=substr($qn,0, strpos($qn, " from"));
$qn="$qn,";
$selc= str_replace("`","", $qn);
$qn= str_replace("`","", $qn);
$my_var=array();
$my_nm=array();
for($m=1;$m<=substr_count($selc, ',');$m++)
{
$my_nm[$m]=substr($qn,0, strpos($qn, ","));
$qn=substr($qn,strpos($qn, ",")+1, strlen($qn));
if(strpos($my_nm[$m]," as ")>0)
{
$my_var[$m]= str_replace(" as ", "~", $my_nm[$m]);
$my_var[$m]= str_replace(" ", "", $my_var[$m]);
$my_var[$m]=substr($my_var[$m],strpos($my_var[$m],"~")+1,strlen($my_var[$m]));
}else
{
$my_var[$m]=substr($my_nm[$m],0, strlen($my_nm[$m]));
$my_var[$m]= str_replace(" ","", $my_var[$m]);
}
}
$rn=mysqli_query($dbc, $main_q);
if($rn)
{
if(mysqli_num_rows($rn)>0)
{
for($t=1;$t<=count($my_var);$t++)
{
$$my_var[$t]=array();
}
while($row=mysqli_fetch_array($rn,MYSQLI_ASSOC))
{
if(mysqli_num_rows($rn)>1)
{
for($t=1;$t<=count($my_var);$t++)
{
${$my_var[$t]}[]=$row[$my_var[$t]];
}
}else{
for($t=1;$t<=count($my_var);$t++)
{
$$my_var[$t]=$row[$my_var[$t]];
}
}
}
if(mysqli_num_rows($rn)>1)
{
for($t=1;$t<=count($my_var);$t++)
{
$GLOBALS[$my_var[$t]]= sel_mr($my_var,$$my_var[$t]);
}
for($t=1;$t<=count($my_var);$t++)
{
return $$my_var[$t];
}
}
if(mysqli_num_rows($rn)==1)
{
for($t=1;$t<=count($my_var);$t++)
{
$GLOBALS[$my_var[$t]]=$$my_var[$t];
}
for($t=1;$t<=count($my_var);$t++)
{
return $$my_var[$t];
}
}
}else
{
for($t=1;$t<=count($my_var);$t++)
{
$GLOBALS[$my_var[$t]]=NULL;
}
for($t=1;$t<=count($my_var);$t++)
{
return $my_var[$t];
}
}
}else
{
for($t=1;$t<=count($my_var);$t++)
{
$my= mysqli_error($dbc);
if($t==1)
{
$err= debug_backtrace();
$err_line=$err[0]['line'];
$err_file=$err[0]['file'];
echo "<font color='#ef0000'>Error at <b>$err_file on line $err_line </b>query --></font><font color='maroon'>$q</font> (<font color='red'> $my </font>)";
}
}
for($t=1;$t<=count($my_var);$t++)
{
for($p=0;$p<count($$my_var[$t]);$p++)
{
$a=$$my_var[$t];
return $a;
}
}
}
}
}
function sel_mr($a,$ab)
{
for($t=1;$t<=count($a);$t++)
{
foreach ($ab as $my)
{
${$a[$t]}[]=$my;
}
}
for($t=1;$t<=count($a);$t++)
{
return $$a[$t];
}
}
?>
注：
您可以將這段代碼保存到一個文件，那麼你可以通過包括文件名
調用這個函數如果你的文件名是q.php（ - >包含q函數） 那麼你可以使用th //dev.mysql：通過包括
<?php
include 'q.php';
q("select user_name from users where user_id=4048");
echo $user_name
?>
http://dev.mysql.com/doc/refman/5.1/en/adding-functions.html創建自己的功能或HTTP另一個文件E碼。 com/doc/refman/5.0/en/mathematical-functions.html創建查詢 – galchen