Unexpected results when Select objects using jq - json

Question

When I add the body to output list, some wrong names get output. I expected it to output only names for nfl subreddit in both examples. Feature or bug? How can I only output the tuples for subreddit nfl?
The file:
{"author":"403and780","author_flair_css_class":"NHL-EDM4-sheet1-col01-row17","author_flair_text":"EDM - NHL","body":"Don't get why we do this but can't have a Grey Cup GDT.","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsn6","is_submitter":false,"link_id":"t3_7v9yqa","parent_id":"t3_7v9yqa","permalink":"/r/hockey/comments/7v9yqa/game_thread_super_bowl_lii_philadelphia_eagles_vs/dtqrsn6/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"hockey","subreddit_id":"t5_2qiel","subreddit_type":"public"}
{"author":"kygiacomo","author_flair_css_class":null,"author_flair_text":null,"body":"lol missed the extra wtf","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsn7","is_submitter":false,"link_id":"t3_7vad8n","parent_id":"t3_7vad8n","permalink":"/r/nfl/comments/7vad8n/super_bowl_lii_game_thread_philadelphia_eagles/dtqrsn7/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"nfl","subreddit_id":"t5_2qmg3","subreddit_type":"public"}
{"author":"shitpostlord4321","author_flair_css_class":null,"author_flair_text":null,"body":"I really hope we get Bleeding Edge before we get the all new all different armor. ","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsn8","is_submitter":false,"link_id":"t3_7v7whz","parent_id":"t3_7v7whz","permalink":"/r/marvelstudios/comments/7v7whz/a_great_new_look_at_iron_mans_avengers_infinity/dtqrsn8/","retrieved_on":1518931297,"score":1,"stickied":false,"subreddit":"marvelstudios","subreddit_id":"t5_2uii8","subreddit_type":"public"}
{"author":"namohysip","author_flair_css_class":null,"author_flair_text":null,"body":"Maybe. I mostly am just doing this to get a story out, and it\u2019s a huge one, so I\u2019m not sure that I\u2019ll be making another fic for many more months. I guess Pokemon Mystery Dungeon just isn\u2019t as popular with the older demographics of AO3.","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsn9","is_submitter":true,"link_id":"t3_7v9psr","parent_id":"t1_dtqrm3t","permalink":"/r/FanFiction/comments/7v9psr/how_do_you_deal_with_bad_reviews/dtqrsn9/","retrieved_on":1518931297,"score":1,"stickied":false,"subreddit":"FanFiction","subreddit_id":"t5_2r5kb","subreddit_type":"public"}
{"author":"SDsc0rch","author_flair_css_class":null,"author_flair_text":null,"body":"if it rates an upvote, I'll click it - I'm not gonna click on low quality \nnot gonna apologize for it either ","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsna","is_submitter":false,"link_id":"t3_7vaam4","parent_id":"t3_7vaam4","permalink":"/r/The_Donald/comments/7vaam4/daily_reminderif_you_see_any_gray_arrows_on_the/dtqrsna/","retrieved_on":1518931297,"score":4,"stickied":false,"subreddit":"The_Donald","subreddit_id":"t5_38unr","subreddit_type":"public"}
{"author":"scarletcrawford","author_flair_css_class":null,"author_flair_text":null,"body":"Honestly, I wanted Takeshi to stay with Poe, but to each their own ship, I guess.","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsnb","is_submitter":false,"link_id":"t3_7upyc0","parent_id":"t1_dtppyry","permalink":"/r/alteredcarbon/comments/7upyc0/season_1_series_discussion/dtqrsnb/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"alteredcarbon","subreddit_id":"t5_3bzvp","subreddit_type":"public"}
{"author":"immortalis","author_flair_css_class":"vikings","author_flair_text":"Vikings","body":"The ghost of MN kickers will haunt this game.","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsnc","is_submitter":false,"link_id":"t3_7vad8n","parent_id":"t3_7vad8n","permalink":"/r/nfl/comments/7vad8n/super_bowl_lii_game_thread_philadelphia_eagles/dtqrsnc/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"nfl","subreddit_id":"t5_2qmg3","subreddit_type":"public"}
{"author":"KryptoFreak405","author_flair_css_class":"48","author_flair_text":"","body":"His original backstory had him training to be an Imperial officer until a commanding officer ordered him to transport a shipment of slaves. He refused, freed the slaves, one of which was Chewie, and defected to become a smuggler","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsnd","is_submitter":false,"link_id":"t3_7vanzc","parent_id":"t1_dtqr5q5","permalink":"/r/StarWars/comments/7vanzc/solo_a_star_wars_story_big_game_tv_spot/dtqrsnd/","retrieved_on":1518931297,"score":1102,"stickied":false,"subreddit":"StarWars","subreddit_id":"t5_2qi4s","subreddit_type":"public"}
{"author":"thwinks","author_flair_css_class":null,"author_flair_text":null,"body":"Oh. TIL","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsne","is_submitter":false,"link_id":"t3_7v8o0z","parent_id":"t1_dtqg97a","permalink":"/r/gifs/comments/7v8o0z/silly_walk_champion/dtqrsne/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"gifs","subreddit_id":"t5_2qt55","subreddit_type":"public"}
{"author":"Mimi108","author_flair_css_class":"lions","author_flair_text":"Lions","body":"The Big. The Dick. The Nick. ","can_gild":true,"controversiality":0,"created_utc":1517788800,"distinguished":null,"edited":false,"gilded":0,"id":"dtqrsnf","is_submitter":false,"link_id":"t3_7vad8n","parent_id":"t3_7vad8n","permalink":"/r/nfl/comments/7vad8n/super_bowl_lii_game_thread_philadelphia_eagles/dtqrsnf/","retrieved_on":1518931297,"score":2,"stickied":false,"subreddit":"nfl","subreddit_id":"t5_2qmg3","subreddit_type":"public"}
Code example 1, which works OK:
$ cat head_rc.txt | jq -r 'select(.subreddit=="nfl") .author'
kygiacomo
immortalis
Mimi108
Code example 2, which is wrong or unexpected to me:
$ cat head_rc.txt | jq -r 'select(.subreddit=="nfl") .body, .author'
403and780
lol missed the extra wtf
kygiacomo
shitpostlord4321
namohysip
SDsc0rch
scarletcrawford
The ghost of MN kickers will haunt this game.
immortalis
KryptoFreak405
thwinks
The Big. The Dick. The Nick.
Mimi108
You can see that author 403and780 commented to a hockey subreddit, not nfl, unfortunately.

Answer 1

jq solution:
jq -r 'select(.subreddit == "nfl") as $o | $o.body, $o.author' head_rc.txt
... as $o - assign filtered object to variable o
The output:
lol missed the extra wtf
kygiacomo
The ghost of MN kickers will haunt this game.
immortalis
The Big. The Dick. The Nick.
Mimi108

Answer 2

Also need to add streaming once I get this syntax correct.
Some good news - you won't need to use the so-called "streaming parser", because your input has already been chopped up. The "streaming parser" is only needed when the input has one or more individually ginormous JSON entities, whereas you have a (long) stream of small JSON objects.
p.s.
As Charles Duffy suggested, the simplest solution to your selection problem is to use parentheses
jq -r 'select(.subreddit=="nfl") | (.body, .author)' input.json
If CSV or TSV makes sense, then change the parentheses to brackets, and tack on #csv or #tsv, e.g.
select(.subreddit=="nfl") | [.body, .author] | #tsv