I wanted to filter my result set to items where a column contained a value from another column — not that it was equal, but like. CONCAT allows me to do this:

nlA.clli_code LIKE CONCAT('%', CONCAT(nle.exchange_area_clli ,'%'))

Alternately, using ||

nlA.clli_code LIKE ('%' || nle.exchange_area_clli || '%')