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

In MySQL concatenating any string to a NULL value results in NULL. You have to check for NULL before concatenate using IFNULL:

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