Why is mysql_fetch_array not executed?

Why is mysql_fetch_array not executed? Reference & lt ;? Phperror_reporting (0); $ conn = mysql_connect ("localhost", "root", "root"); // enter the database connection information mysql_select_db ("a1209173000 "); // why is mysql_fetch_array not executed?
Reference

Error_reporting (0 );
$ Conn = mysql_connect ("localhost", "root", "root"); // enter the database connection information.
Mysql_select_db ("a1209173000"); // enter the database name
$ ValA = $ _ POST ["valA"];
If ($ valA! = ""){
$ SQL = "select * from table where chepai = '". $ valA ."'";
$ Result = mysql_query ($ SQL );
While ($ arr = mysql_fetch_array ($ result ))
{
Echo $ arr ["name"]."
";
}
} Else {
?>

}
?>

By adding echo output after each row, we can find that while ($ arr = mysql_fetch_array ($ result) is not executed. what is wrong? $ SQL is normal.
------ Solution --------------------

$result=mysql_query($sql);
if(mysql_error()){
  echo mysql_errno() . ": " . mysql_error() . "\n";
}

Check whether an error is reported?
------ Solution --------------------
In
Mysql_select_db ("a1209173000"); // enter the database name
And then add
Mysql_query ('set names gbk ');
This is because the operated data is inconsistent with the default character set of the database.