[How to convert values in certain colum to comma separated list?]

In your query you can use the GROUP_CONCAT function and GROUP BY the field you don't want duplicated to achieve that result. Here's an example table with duplicated data:

 

State	City
New York	New York City
New York	Syracuse
California	Los Angeles
California	San Francisco
Texas	Austin

 

With the below query

SELECT state, GROUP_CONCAT(city SEPARATOR ", ") AS cities FROM table GROUP BY state[/code]

The data will now be displayed as

state	cities
New York	New York City, Syracuse
California	Los Angeles, San Francisco
Texas	Austin

 

You can also sort the cities or remove duplicates from that field as well with additional functions inside the GROUP_CONCAT. More information about GROUP_CONCAT can be found at https://dev.mysql.com/doc/refman/8.0/en/group-by-functions.html#function_group-concat

 

 

[How to replace null value to other string words]

Try checking if the field is not null and just reverse the results:

<textFieldExpression><![CDATA[$F{fieldName} != null ? $F{fieldName} : "-"]]></textFieldExpression>[/code]