如何从mysql中的两个表中选择两列 [英] how to select two columns from two tables in mysql

问题描述

我正在尝试执行此查询，但出现错误未定义索引: lname".我要从表a和 从其他表中选择column(lname)b.所以请帮助我.

I am trying to execute this query but i got error " Undefined index: lname".I want to count row from one column(fname) from table a and select column(lname) from other table b. so please help me.

    $result = mysql_query("SELECT COUNT(fname),lname FROM a,b");
    while ($row = mysql_fetch_array($result))
    {
      echo "<tr><td>";
      echo $row['lname'];
      echo "</td>";
      echo "<td>";
      echo $row['COUNT(fname)'];
      echo "</td></tr>";
    }

推荐答案

您需要使用别名.使用这个:

You need to use an alias. Use this:

$result = mysql_query("SELECT COUNT(fname) AS countfname,lname FROM a,b");
while ($row = mysql_fetch_array($result))
{
  echo "<tr><td>";
  echo $row['lname'];
  echo "</td>";
  echo "<td>";
  echo $row['countfname'];
  echo "</td></tr>";
}

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