免责声明:我知道我的代码中不推荐使用 mysql 函数。这在我的待办事项 list 上。
我有一个 MySql 选择,为我提供房屋预订系统中不同项目的季节。
种类:
Low season: 2010-01-01, 2010-03-01, 100 //meaning start,end,price
这是我的第一个 sql:
while($season_row=mysql_fetch_assoc($season_res)){
$seasonsArray[$season_row['id_item']][] = array(
$season_row['season_start'],
$season_row['season_end'],
$season_row['daily_price']
);
}
日期在此处定义(以 YYYY-mm-dd
形式到达函数):
function seasonPrice($from,$to,$requested_item){
$start = round(strtotime($from)/86400)*86400; // like 2008-01-01
$end = round(strtotime($to)/86400)*86400; // to 2015-01-01
$formattedStart = date('Y-m-d', $start);
$formattedEnd = date('Y-m-d', $end);
现在我需要在 $seasonsArray
的项目之间循环 2 个日期,然后检查该项目在该特定日期的价格。
我这样做的是:
foreach($seasonsArray as $item=>$value){
for( $thisDay = $start; $thisDay < $end; $thisDay = $thisDay + 86400){
foreach($value as $innerValue){
$season_start = roundToSeconds($innerValue[0]);
$season_end = roundToSeconds($innerValue[1]);
if($thisDay >= $season_start && $thisDay <= $season_end) {
$foundPrice[] = round($innerValue[2]);
}
}
$thisSerie[] = array($thisDay * 1000, isset($foundPrice) ? $foundPrice[0] : 0);
// security check to avoid double assigned seasons to same day
if(count($foundPrice) > 1){ die('There is double bookings in item: '.$item);}
unset($foundPrice);
}
$seasonPrices[] = array(
'data'=> $thisSerie,
'label'=> 'House ID: '.$item,
);
}
但我得到: fatal error :允许的内存大小 100663296 字节已耗尽
有什么建议可以改进我的代码以不需要那么多内存吗?或者是否存在错误而我没有看到它?
最佳答案
我会生成一系列日期并加入您的季节表,然后使用单个查询来获取所需的结果集,例如:
SELECT dates.Date,
coalesce(s.price, 0) AS price
FROM
(SELECT a.Date
FROM
( SELECT curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a)) DAY AS Date, '0' AS price
FROM
(SELECT 0 AS a
UNION ALL SELECT 1
UNION ALL SELECT 2
UNION ALL SELECT 3
UNION ALL SELECT 4
UNION ALL SELECT 5
UNION ALL SELECT 6
UNION ALL SELECT 7
UNION ALL SELECT 8
UNION ALL SELECT 9) AS a
CROSS JOIN
(SELECT 0 AS a
UNION ALL SELECT 1
UNION ALL SELECT 2
UNION ALL SELECT 3
UNION ALL SELECT 4
UNION ALL SELECT 5
UNION ALL SELECT 6
UNION ALL SELECT 7
UNION ALL SELECT 8
UNION ALL SELECT 9) AS b
CROSS JOIN
(SELECT 0 AS a
UNION ALL SELECT 1
UNION ALL SELECT 2
UNION ALL SELECT 3
UNION ALL SELECT 4
UNION ALL SELECT 5
UNION ALL SELECT 6
UNION ALL SELECT 7
UNION ALL SELECT 8
UNION ALL SELECT 9) AS c) a
WHERE a.Date BETWEEN '$from' AND '$to'
ORDER BY a.Date) dates
LEFT JOIN seasons s ON dates.Date BETWEEN s.start AND s.END
复杂的内部查询避免了创建临时表(取自 generate days from date range ),并且工作时间长达 1000 天,但创建临时表就可以了。
关于php - 循环内循环达到内存限制,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20893444/