MySQL Tutorial/Aggregate Functions/GROUP CONCAT

GROUP_CONCAT(expr) returns a string result with the concatenated non-NULL values from a group

The full syntax is as follows:

   <source lang="sql">

GROUP_CONCAT([DISTINCT] expr [,expr ...]

            [ORDER BY {unsigned_integer | col_name | expr}
                [ASC | DESC] [,col_name ...]]
            [SEPARATOR str_val])</source>