mysql group_concat with ignoring empty string column

Question

MYSQL group_concat() function by default ignore null columns but it didn't ignore empty string columns. I have a field which is mediumtext type and not null. When I am using group_concat function on that the query generated unwanted ',,,' this type of value. How can i avoid this? Thanks in advance for your valuable time.

Answer 1

Transfer empty string to null:

NULLIF(column1,'')

• NULLIF(expr1,expr2):
  • Return NULL if expr1 = expr2

Answer 2

Use GROUP_CONCAT with IF(expr1,expr2,expr3), assume that you want concat column1:

GROUP_CONCAT(IF(column1='', null, column1))