I thought this was a dragon fruit but they sent me here. Does anyone know what kind of Euphorbia this is? I want to take better care of it.

This plant came with the house I bought 10 years ago. It got huge in the back yard in a huge pot but when we did a remodel we had to move it and now it’s grown again but not in an ideal spot. Currently it’s located in a breezeway with only about three hours of sun a day and it gets bumped into frequently so I want to move it but I’m not sure where is best because I don’t know what it is. TIA for any replanting help or ID. I’m in Phoenix if that helps.