[SQL] function array_to_string(text[]) does not exist

[Victor Sterpu]

Hello

When I run :
SELECT array_to_string(array_agg(CONCAT(CAST (ltrv1.val_min AS CHAR), 
'-', CAST(ltrv1.val_max AS CHAR), ' ', ltrv1.comentarii)))
FROM lab_tests_reference_values ltrv1
GROUP BY ltrv1.val_min, ltrv1.val_max, ltrv1.comentarii;
I get the error:
ERROR:  function array_to_string(text[]) does not exist
LINE 1: SELECT array_to_string(array_agg(CONCAT(CAST (ltrv1.val_min ...
               ^
HINT:  No function matches the given name and argument types. You might 
need to add explicit type casts.

I tryed to cast but it's still not working.

Thanku you.