我想截取一个字符串的特定几个字符,然后我该怎么使用呢?
$sql = "SELECT ID,IDNM FROM aa
$data = $this->adapter->query ($sql, $params);
$result = array ();
foreach ( $data as $item ) {
$item ["IDNM"] = $item ["ID"] . "_" . $item ["IDNM"];
原本数据是这样的。。
然后我想修改成
$sql = "SELECT substr(ID,-4),IDNM FROM aa
$data = $this->adapter->query ($sql, $params);
$result = array ();
foreach ( $data as $item ) {
$item ["IDNM"] = $item ["ID"] . "_" . $item ["IDNM"];
但是这样出错了。应该怎么修改?