PHP MySQL 函数   http://www.w3school.com.cn/php/php_ref_mysql.asp

mysql_query  //查询

$str .= ‘"buy":"‘.mysql_num_rows($rs).‘",‘;
$str .= ‘"sell":"‘.mysql_num_rows($rs1).‘",‘;
$str .= ‘"coll":"‘.mysql_num_rows($rs2).‘"‘;  //结果

mysql_free_result($rs2);
mysql_free_result($rs1);
mysql_free_result($rs); //释放

原文：http://www.cnblogs.com/maruco2020/p/4521808.html