1问题描述:根据始末日期查询数据,由于数据库数据量大,用between and很慢,就添加了year,month,day字段,在比较年月日的时候有substr和date两种方法,两种都尝试过每次加载时间都在变化,也没找到相关的技术文章。理论上是两种速度都差不多,还是有相对快的方法?感谢每一个答题者。
2.相关代码片段:
//substr
if(substr($startTime,0,4) == substr($endTime,0,4)){
$str .= " L.year = ".substr($startTime,0,4);
if(substr($startTime,4,2) == substr($endTime,4,2)){
$str .= " and L.month = ".substr($startTime,4,2);
if(date('Ynd',strtotime($startTime)) == date('Ynd',strtotime($endTime))){
$str .= " and day = ".date('d',strtotime($startTime));
}else{
$str .= " and log_date between '$startTime' and '$endTime' ";
}
}else{
$str .= " and log_date between '$startTime' and '$endTime' ";
}
}else{
$str .= " L.log_date between $startTime and $endTime";
}
//date
if(date('Y',strtotime($startTime)) == date('Y',strtotime($endTime))){
$str = " where year = ".date('Y',strtotime($startTime));
if(date('Yn',strtotime($startTime)) == date('Yn',strtotime($endTime))){
$str .= " and month = ".date('n',strtotime($startTime));
if(date('Ynd',strtotime($startTime)) == date('Ynd',strtotime($endTime))){
$str .= " and day = ".date('d',strtotime($startTime));
}else{
$str .= " and log_date between '$startTime' and '$endTime' ";
}
}else{
$str .= " and log_date between '$startTime' and '$endTime' ";
}
}else{
$str = " where log_date between '$startTime' and '$endTime' ";
}
给我你的怀抱2017-05-16 13:11:05
不管是用substr截取前4位,还是date('Y'),你都是php的执行而已,php这点时差忽略不记,最终得到的sql是一样的,并不会影响到数据库的查询效率。
你应该贴出需要执行的sql语句来让大家看看是否能再优化