Group_Concat in Concat not working with NULL values

Question

I have a table

CREATE TABLE IF NOT EXISTS `dept` (
  `did` int(11) NOT NULL,
  `dname` varchar(50) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSE         


        

Answer 1

try this, use COALESCE

.., COALESCE(dname, 'NULL'),..

making it NULL string visible. SQLFIDDLE DEMO