mysql实现upsert

• upsert(update or insert), 即更新或写入。
• MySQL中实现upsert操作方式：
  思路：通过判断插入的记录里是否存在主键索引或唯一索引冲突，来决定是插入还是更新。当出现主键索引或唯一索引冲突时则进行update操作，否则进行insert操作。
  实现：使用 ON DUPLICATE KEY UPDATE

来看看下面具体实现过程。

一、准备数据表

CREATE TABLE `demo` (  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,  `a` tinyint(1) unsigned NOT NULL DEFAULT '0',  `b` tinyint(1) unsigned NOT NULL DEFAULT '0',  `c` tinyint(1) unsigned NOT NULL DEFAULT '0',  `d` tinyint(1) unsigned NOT NULL DEFAULT '0',  `e` tinyint(1) unsigned NOT NULL DEFAULT '0',  `f` tinyint(1) unsigned NOT NULL DEFAULT '0',  PRIMARY KEY (`id`),  UNIQUE KEY `unq_a_b_c` (`a`,`b`,`c`)) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;

注意：表中存在两处索引,id为主键索引，a,b,c为联合唯一索引。

二、写入初始数据

insert into test.demo(a,b,c,d,e,f) values(1,1,1,1,1,1);

此时存在由abc散列组成唯一索引数据：1，1，1。

三、进一步实现

insert into demo(a,b,c,d,e,f) values(1,1,1,2,2,2) ON DUPLICATE KEY UPDATE a=2,b=2,c=3,d=4,e=5,f=6;

因为已经存在由abc三列组成唯一索引数据：1，1，1，本次又写入demo(a,b,c,d,e,f) values(1,1,1,2,2,2)，会造成唯一索引冲突。因此，会触发ON DUPLICATE KEY 后面的 UPDATE a=2,b=2,c=3,d=4,e=5,f=6操作。

至此，已经实现upsert功能。请记住 ON DUPLICATE KEY UPDATE的用法。

实现mysql的批量更新

 insert into statistic_customer(customer_id,current_period,period_number,client_upload_bill,update_time) values (1,201604,100,100,1540470829), (314,201604,100,100,1540470829), (315,201604,100,100,1540470829), (316,201611,100,100,1540470829) ON DUPLICATE KEY UPDATE customer_id=values(customer_id), current_period=values(current_period), period_number=values(period_number), client_upload_bill=values(client_upload_bill), update_time=values(update_time)

public static function test()    {        $updateData = [            [                'customer_id' => 1,                'current_period' => 201604,                'period_number' => 100,                'client_upload_bill' => 100,                'update_time' => time(),            ],            [                'customer_id' => 314,                'current_period' => 201604,                'period_number' => 100,                'client_upload_bill' => 100,                'update_time' => time(),            ],            [                'customer_id' => 315,                'current_period' => 201604,                'period_number' => 100,                'client_upload_bill' => 100,                'update_time' => time(),            ],            ['customer_id' => 316,                'current_period' => 201611,                'period_number' => 100,                'client_upload_bill' => 100,                'update_time' => time(),            ],        ];        $sql = self::buildSQL('statistic_customer', $updateData);        DB::insert($sql);    }    private static function buildSQL(string $tableName, array $updateData): string    {        $sql = "insert into {$tableName}(";        $keys = array_keys($updateData[0]);        $sql .= implode(',', $keys);        $sql .= ') values';        $valuesStr = '';        foreach ($updateData as $value) {            $valuesStr .= '(' . implode(',', array_values($value)) . '),';        }        $sql .= rtrim($valuesStr, ',');        $sql .= ' ON DUPLICATE KEY UPDATE ';        $updateStr = '';        foreach ($keys as $key) {            $updateStr .= "{$key}=values($key),";        }        $sql .= rtrim($updateStr, ',');        return $sql;    }