douchuituo3032 2011-12-12 03:53
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尝试使用UNION ALL查询两个表时出错

I'm trying to query a single result from two tables in my database. Here is my code:

$pageid = mysql_real_escape_string($_GET['id']);
$query = sprintf("(SELECT * FROM classifieds WHERE pageid = '$pageid' LIMIT 1)
UNION ALL
(SELECT * FROM resumes WHERE pageid = '$pageid' LIMIT 1)");
$result = mysql_query($query);

while ($row = mysql_fetch_array($result)) {
    echo $row['title'] . "<br/>";
    }

pageid is a URL variable. This code is trying to use that variable, query the database with it, and return the result. I get this error:

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource

Hitting a wall here. Can't figure out why this error keeps happening. Any help == thanks.

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  • dpwgzi7987 2011-12-12 03:56
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    When using UNION the number of columns and types of columns, of both queries must be same.

    Now as you are quering two different tables, I guess it is safe to assume that either number of columns are different or corresponding column types do not match.

    try using something like this

    select col1, col2 from classifieds.......
    Union All
    select col1, col2
    

    but again, number and corresponding column types should be same.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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