MongoDB query how to output only part of the field content

Shulou Source: shulou.com Published: 2022-06-01 07:51:16 10月04日 Update

For example, the collection test has three columns id,url and data. Now we only want to output the id and url fields, which can be looked up as follows:

> db.test.find ({}, {id: 1, url: 1})

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f39d"), "url": "http://info.zjktx.cn/urlsearch.php?info_flag=6&url=915ad2673221b5ab17ba29e24d00efc3"}

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f39e"), "url": "http://mp.weixin.qq.com/s?__biz=MzIwOTY0NjY5NA==&mid=2247487505&idx=3&sn=8bdfc5b35eaa5eb7d2dbc2ff6247bf06&chksm=9771f518a0067c0e982d834821f9a44b7eea39f60cff8d50886175bbe1c93b27c70a8af9bfd9&scene=0#rd"}

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f39f"), "url": "http://weibo.com/6432427115/GcR5t3Fh9"}

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f3a0"), "url": "http://weibo.com/6503912228/GcR5ftPt7"}

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f3a1"), "url": "http://mp.weixin.qq.com/s?__biz=MzU1NzE3MTEzOQ==&mid=2247486132&idx=7&sn=e031435df54cc5c6dcbdab4136c73222&chksm=fc38a218cb4f2b0e0b581ea5d7ef13f95d29321b385fe51137c8cd102b715ebfb75c284aacb0&scene=0#rd"}

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f3a2"), "url": "http://mp.weixin.qq.com/s?__biz=MzAxOTMxMTAxOA==&mid=2650490009&idx=2&sn=020a9d674e4f48da10f3ed376bdda67f&chksm=83c7145cb4b09d4a153515ef56755098bccfbca92f7fb379621ffbe4177fc8431181a2d1f2cc&scene=0#rd"}

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f3a3"), "url": "http://mp.weixin.qq.com/s?__biz=MzI0NTU3NDY1NQ==&mid=2247487947&idx=1&sn=0daadc7945dd56fa7f1c7c61557646ed&chksm=e94d2f5bde3aa64dc6578e1ce9997c5cbe57fc0500222dd9939da33877168afb3297045a50f8&scene=0#rd"}

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f3a4"), "url": "http://weibo.com/ttarticle/p/show?id=2309614230624788536034"}

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f3a5"), "url": "http://mp.weixin.qq.com/s?__biz=MzA5ODU0NzQ4OA==&mid=2649879715&idx=1&sn=5bdf0a2ca64b51df037252da73fe9d1c&chksm=888ab6ecbffd3ffa97bc454aef5e490eb8c4d5bd79e7dd61c833107dd907e3b7b6600bb7d111&scene=0#rd"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3a6"), "url": "http://www.qddtj.com/qdtj/961445.html"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3a7"), "url": "http://weibo.com/3078765485/GcQPzAWxR"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3a8"), "url": "http://weibo.com/1981850854/GcJ0KkXuz"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3a9"), "url": "http://weibo.com/2824592185/GcQQ9Dpu4"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3aa"), "url": "http://weibo.com/6456176195/GcQR69zDX"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3ab"), "url": "http://weibo.com/5996334075/GcR3UrMgN"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3ac"), "url": "http://weibo.com/3802294663/GcR5LDlyR"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3ad"), "url": "http://weibo.com/2428661490/GcQZL45qh"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3ae"), "url": "http://weibo.com/1762661765/GcR0LrC9O"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3af"), "url": "http://weibo.com/6135218321/GcQH544Rs"}

{"_ id": ObjectId ("5ad8a51cb5cec3000b17f3b0"), "url": "http://weibo.com/5996334075/GcR3OewDh"}

Type "it" for more

Note: the first parameter is the query condition, and an empty parameter represents the query for all

/ / if you do not want a field, you can use the method of excluding fields

For example, exclude the contents of the data field:

> db.test.find ({}, {data: 0})

{"_ id": ObjectId ("5ad8a51bb5cec3000b17f39d"), "url": "http://info.zjktx.cn/urlsearch.php?info_flag=6&url=915ad2673221b5ab17ba29e24d00efc3"," error: "BSON document too large (25962119 bytes)-the connected server supports BSON document sizes up to 16793598 bytes."}