php mysql百万级数据去除重复数据

<?php教程
//定义一个数组，用于存放排重后的结果
$result = array();
//读取uid列表文件
$fp = fopen('test.txt', 'r');

while(!feof($fp))
{
$uid = fgets($fp);
$uid = trim($uid);
$uid = trim($uid, " ");
$uid = trim($uid, " ");

if($uid == '')
{
continue;
}
//以uid为key去看该值是否存在
if(empty($result[$uid]))
{
$result[$uid] = 1;
}
}

fclose($fp);

//将结果保存到文件
$content = '';
foreach($result as $k => $v)
{
$content .= $k." ";
}
$fp = fopen('result.txt', 'w');
fwrite($fp, $content);
fclose($fp);
?>　　

<?php
//定义数组，用于存放排重后的结果
$result = array();
//读取第一个uid列表文件，放入$result_1
$fp = fopen('test_1.txt', 'r');
while(!feof($fp))
{
$uid = fgets($fp);
$uid = trim($uid);
$uid = trim($uid, " ");
$uid = trim($uid, " ");
if($uid == '')
{
continue;
}
//以uid为key写入$result，如有重复就会覆盖
$result[$uid] = 1;
}
fclose($fp);
//读取第二个uid列表文件，并进行排重操作
$fp = fopen('test_2.txt', 'r');
while(!feof($fp))
{
$uid = fgets($fp);
$uid = trim($uid);
$uid = trim($uid, " ");
$uid = trim($uid, " ");
if($uid == '')
{
continue;
}
//以uid为key去看该值是否存在
if(empty($result[$uid]))
{
$result[$uid] = 1;
}
}
fclose($fp);
//$result里保存的就排重以后的结果，可以输出到文件，代码省略
?>

//自动计算二个字段的值赋给另一字段sql

$sql ="update table set sum = mathe +language";

//求一个字段列的数据总和

$sql = "select sum(sum) from tables";

//下们我们来看个实例

/*
创建表
CREATE TABLE `cc`.`sumtable` (
`id` INT( 4 ) NOT NULL ,
`a1` INT( 4 ) NOT NULL ,
`a2` INT( 4 ) NOT NULL ,
`summ` INT( 8 ) NOT NULL
) ENGINE = InnoDB

插入记录

INSERT INTO `cc`.`sumtable` (
`id` ,
`a1` ,
`a2` ,
`summ`
)
VALUES (
'1', '5', '5', '0'
), (
'2', '6', '5', '0'
);
*/

//自动计算二个字段的值赋给另一字段sql
update sumtable set summ = a1+a2

//求和
SELECT sum( summ ) FROM sumtable
sum(summ) 
21

//本站原创文章转载注明来源www.111cn.net

$this->beginTransaction();
$this->exec('update people set age=2');

//$step1 = mysql教程_error();//你的类里，改成如果执行sql错误，获取错误代码，相应的函数

THEN
#非订单类
IF EXISTS (SELECT dtLast FROM tMaxCode WHERE iType=V_iType LIMIT 0,1)
THEN 
SELECT IFNULL(iMax,0)+1 INTO iCode FROM tMaxCode WHERE iType=V_iType;
ELSE
SET iCode=1;
END IF;
SELECT IFNULL(iMax,0)+1 INTO iCode FROM tMaxCode WHERE iType=V_iType;
ELSE
#订单类
IF EXISTS (SELECT iMax FROM tMaxCode WHERE iType=V_iType AND DATEDIFF(dtLast,CURRENT_DATE)=0 LIMIT 0,1)
THEN 
#上次生成时间是当天
  SELECT IFNULL(iMax,0)+1 INTO iCode FROM tMaxCode WHERE iType=V_iType;
ELSE
SET iCode=1;
END IF;
END IF;