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Asked: 2026-05-11T20:01:36+00:00

I have PHP 5 code accessing a MyISAM table on MySQL 5 server. The

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I have PHP 5 code accessing a MyISAM table on MySQL 5 server. The query looks like this:

SELECT CONCAT(fName1,' ',mName2,' ',lName3) AS userName 
    FROM users 
    WHERE level > 10

When there’s no mName filled in, I am expecting output like “fname lname” , but I’m getting “” (empty string) instead (the number of rows returned is correct). Where am I making a mistake?

PHP code:

<?php
$result = mysql_query($the_above_query);
while ($result_row = mysql_fetch_assoc($result)) {
    // do stuff with the name
    // except I'm getting empty strings in $result_row['userName']
}

Relevant part of table structure:

CREATE TABLE users {
    /* -snip- */ 
    `fName1` varchar(50) default NULL,      
    `mName2` varchar(50) default NULL,      
    `lName3` varchar(50) default NULL,      
    `level` int(11) default 0,      
    /* -snip- */ 
} ENGINE=MyISAM DEFAULT CHARSET=utf8;

(also, is this way (column concatenation in MySQL) a good idea, or should I fetch the columns to PHP and join them there?)

Turns out that I was getting back a NULL; PHP treats a returned NULL and empty string(“”) similarly, you’d have to compare with === to see the difference.

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1 Answer

  1. Editorial Team

    From google: http://bugs.mysql.com/bug.php?id=480

    [23 May 2003 4:32] Alexander Keremidarski

    Thank you for taking the time to write to us, but this is not
    a bug. Please double-check the documentation available at
    http://www.mysql.com/documentation/ and the instructions on
    how to report a bug at http://bugs.mysql.com/how-to-report.php

    This is doccumented behaviour of CONCAT() function.

    From Manual chapter 6.3.2 String Functions

    CONCAT(str1,str2,…)
    Returns the string that results from concatenating the arguments. Returns NULL if any
    argument is NULL

    Use CONCAT_WS() instead or wrap NULLable paremeters with IFNULL() function.

    Documentation and usage for CONCAT_WS: http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_concat-ws

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