# 示例一:所有字段
# select * from galance20170801
searchRes = db_coll.find()
# 或者searchRes = db_coll.find({})
# 示例二:用字典指定要显示的哪几个字段
# select _id,key from galance20170801
queryArgs = {}
projectionFields = {'_id':True, 'key':True} # 用字典指定
searchRes = db_coll.find(queryArgs, projection = projectionFields)
# 结果{'_id': 'B01EYCLJ04', 'key': 'pro audio'}
# 示例三:用字典指定去掉哪些字段
queryArgs = {}
projectionFields = {'_id':False, 'key':False} # 用字典指定
searchRes = db_coll.find(queryArgs, projection = projectionFields)
# 结果{'activity': False, 'avgStar': 4.3, 'color': 'Yellow & Black', 'date':
'2017-08-01'}
# 示例四:用列表指定要显示哪几个字段
# select _id,key,date from galance20170801
queryArgs = {}
projectionFields = ['key','date'] # 用列表指定,结果中一定会返回_id这个字段
searchRes = db_coll.find(queryArgs, projection = projectionFields)
# 结果{'_id': 'B01EYCLJ04', 'date': '2017-08-01', 'key': 'pro audio'}
(5.1.2)指定查询条件
(5.1.2.1).比较:=,!=,>,<,>=,<=
$ne:不等于(not equal)
$gt:大于(greater than)
$lt:小于(less than)
$lte:小于等于(less than equal)
$gte:大于等于(greater than equal)