旧版主题筛选函数

要做新的了，把老的放出来晒晒……

性能上没太大问题，但是数据结构是写死的，灵活性太差。

正在研究新函数，要换一种计算方式了。

function get_b($b,$k,$v,$t,$a){

$pdo=init();

$needn=$a+1;$needl=$a;$bq=count($b);

if(!$v){$samen=array();$samel=array();}

else{

$sql='';

if($bq>1){$sql.='SELECT * FROM (';}

$crc=$bq;

foreach($b as $row){

$crc--;

$sql.='(SELECT `c`,`d`,`t` FROM `b` WHERE `b`="'.$row.'" AND `'.$k.'`='.$v.' '.($t?'AND `t`<='.$t:'').' ORDER BY `'.$k.'` DESC, `t` DESC LIMIT '.($a+1).')';

if($crc){$sql.=' UNION ALL ';}

}

if($bq>1){

$sql.=') AS `tempn` ORDER BY `'.$k.'` DESC, `t` DESC LIMIT '.($a+1);

}

$sql.=' ; ';

if($t){

if($bq>1){$sql.='SELECT * FROM (';}

$crc=$bq;

foreach($b as $row){

$crc--;$sql.='(SELECT `c`,`d`,`t` FROM `b` WHERE `b`="'.$row.'" AND `'.$k.'`='.$v.' AND `t`>'.$t.' ORDER BY `'.$k.'` ASC, `t` ASC LIMIT '.$a.')';

if($crc){$sql.=' UNION ALL ';}

}

if($bq>1){$sql.=') AS `templ` ORDER BY `'.$k.'` ASC, `t` ASC LIMIT '.$a;}

}

$sameq=$pdo->query($sql);

$samen=$sameq->fetchAll(PDO::FETCH_ASSOC)?:array();

if($t){$sameq->nextRowset();$samel=$sameq->fetchAll(PDO::FETCH_ASSOC)?:array();}

else{$samel=array();}

}

$needn-=count($samen);$needl-=count($samel);

if(!$needn && !$needl){

$diffn=array();$diffl=array();

}

else{

$sql='';

if($needn){

if($bq>1){$sql.='SELECT * FROM (';}

$crc=$bq;

foreach($b as $row){

$crc--;

$sql.='(SELECT `c`,`d`,`t` FROM `b` WHERE `b`="'.$row.'" '.($v?'AND `'.$k.'`<'.$v:'').' ORDER BY `'.$k.'` DESC, `t` DESC LIMIT '.$needn.')';

if($crc){$sql.=' UNION ALL ';}

}

if($bq>1){

$sql.=') AS `tempn` ORDER BY `'.$k.'` DESC, `t` DESC LIMIT '.$needn;

}

$sql.=' ; ';

}

if($needl && $v){

if($bq>1){$sql.='SELECT * FROM (';}

$crc=$bq;

foreach($b as $row){

$crc--;$sql.='(SELECT `c`,`d`,`t` FROM `b` WHERE `b`="'.$row.'" AND `'.$k.'`>'.$v.' ORDER BY `'.$k.'` ASC, `t` ASC LIMIT '.$needl.')';

if($crc){$sql.=' UNION ALL ';}

}

if($bq>1){$sql.=') AS `tempn` ORDER BY `'.$k.'` ASC, `t` ASC LIMIT '.$needl;

}

}

$diffq=$pdo->query($sql);

$diffn=$needn?($diffq->fetchAll(PDO::FETCH_ASSOC)?:array()):array();

if(!$needl || !$v){$diffl=array();}

else{if($needn){$diffq->nextRowset();}$diffl=$diffq->fetchAll(PDO::FETCH_ASSOC)?:array();}

}

$needn-=count($diffn);$needl-=count($diffl);

$res=array();

$res['t']=array_merge($samen,$diffn);

$res['b_next']=$needn?null:array_pop($res['t']);

$res['b_last']=($needl==$a)?null:end(array_merge($samel,$diffl));

$res['t']=array_column($res['t'],'t');

return $res;

}