NET
23 For all day long his work produces pain and frustration, and even at night his mind cannot relax. This also is futile!
Darby
23 For all his days are sorrows, and his travail vexation: even in the night his heart taketh no rest. This also is vanity.
KJV
23 For all his days [are] sorrows, and his travail grief; yea, his heart taketh not rest in the night. This is also vanity.