https://dwt.life/tag/mongodb/ https://dwt.life/archives/191/ 2022-02-14T01:29:03+08:00 db.idap_zl.insert({array:[]})db.idap_zl.insert({array:[1,2,3,4,5]})db.idap_zl.find({array:{$elemMatch:{$ne:null}}})一、elemMatch和elemMatch和nedb.Collection.find({array:{$elemMatch:{$ne:null}}})二、$wheredb.Collection.find({$where:"this.array.length>0"})三、not和not和sizedb.Collection.find({array: {$not: {$size: 0}}})四、'.'路径和$existsdb.Collection.find({{'array.0': {$exists: 1}}})五、exists和exists和nedb.Collection.find({ array: { $exists: true, $ne: [] } })六、$gtdb.Collection.find({ array: { $gt: [] } })