MySQL returning an empty field: CONCAT(nonEmpty1,empty2,nonEmpty3) = NULL

Question

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 us         


        

Answer 1

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