以 11.2 为例 ， 注意必须要与数据库版本对应
下载如下两个文件
instantclient-basic-linux.x64-11.2.0.4.0.zip https://download.oracle.com/otn/linux/instantclient/11204/instantclient-basic-linux.x64-11.2.0.4.0.zip
instantclient-sdk-linux.x64-11.2.0.4.0.zip https://download.oracle.com/otn/linux/instantclient/11204/instantclient-sdk-linux.x64-11.2.0.4.0.zip

以上两个文件解压到 /usr/local/lib/instantclient 目录
增加环境变量 ~/.bashrc
export ORACLE_HOME=/usr/local/lib/instantclient
export LD_LIBRARY_PATH=$ORACLE_HOME

安装 oci8 扩展
进入php源码包
./configure --with-php-config=/usr/local/php7.2/bin/php-config --with-oci8=instantclient,/usr/local/lib/instantclient,11.2

安装 pdo_oci 扩展
./configure --with-php-config=/usr/local/php7.2/bin/php-config --with-pdo-oci=instantclient,/usr/local/lib/instantclient,11.2

===========================

使用

原生连接
$conn = OCILogon('system', 'aa123456', '192.168.1.184/orcl');
$stid = oci_parse($conn, 'SELECT * FROM TEST2.TAB2');
oci_execute($stid);
while ($row = oci_fetch_array($stid, OCI_ASSOC+OCI_RETURN_NULLS)) {
print_r($row);
}
pd(11);

yii 连接
$ip = '192.168.1.184';
$port = 1521;
$dbname= 'ORCL'; // 数据库名必须大写
$username = 'system';
$password = 'aa123456';
$charset = 'utf8';
$driver = \Yii::createObject([
'class' => 'yii\db\Connection',
'dsn' => "oci:dbname=//$ip:$port/$dbname;", // Oracle
'username' => $username,
'password' => $password,
'charset' => $charset,
]);

$sql = 'select * from TEST2.TAB2';
$d = $driver->createCommand($sql)->queryAll();
pd($d);

安装参数 https://www.cnblogs.com/mython/p/12931648.html